Is homosexuality objectively and scientifically natural?

"Nature had created sexual organs merely for reproduction and hence naturally they should be used merely for reproduction" I believed that I've grown immune to this sentence, years ago when I started writing about homosexuality I would often get these type of comments from conservatives. I would get agitated easily and ask them to tell, what is so natural about airplane technology and so on (read my earlier ranting here)
Recently I was given the same reason, but the difference was that the person who stated this was pro-LGBT. Needless to say, that person agreed that airplane technology is unnatural but acceptable nonetheless.
The argument put forward was that homosexuality should be accepted because of the free will of individual rather than it being a natural thing. The purpose of sex is the reproduction and homosexual relationship doesn't fulfill this purpose, we have to look into the matter in an objective and scientific way without getting emotional on the issue. Masturbation and contraception are equally unnatural and even though it is unnatural it is accepted as a person is exercising the free will of an individual.
But I have several problems with this stand which I would like to point out here,
Firstly, the argument of homosexuality being unnatural historically is put not to explain the sexual behavior of human under scientific curiosity and there is hardly a question of objectivity but more about that later. That 'Homosexuality is unnatural' was put to dehumanize and demean homosexuals as Deviant or sick people. Using the word 'unnatural' today would still have a negative impact and would not generate acceptance in society.
On the other hand, saying one have free will and one becomes deviant is an ideology that is appropriate for church.
The god does not like homosexuality but gave us free will and due to satanic temptations, some come to like it and hence they are evil is the Christian theology. Homosexuality is a sin, we don't hate sinner who having free will have fallen to Satan's plan but hate the sin which is satanic' this is an age old logic put forward by the conservative.
When the western world became disillusioned with the church, the state and church were separated and so was the people approach to look at things, but it couldn't be said that it cut the chord that instant with the culture, which the church governed and imposed its ideology upon for centuries. They desperately needed a new vocabulary to justify their innate homophobia and invented words like unnatural, Deviant etc. homosexual were not sinner now but diseased and homosexuality was not satanic but sickness. The conservative felt validated by these scientific 'findings"' and quickly adapted to this rational sounding argument.
What was it, if not a mere change of words?
Somehow a person could still accept the homosexual as equal healthy being just because they have free will within this unnatural framework is very surprising, I must congratulate the person, but I doubt many would be able to do the same.
Secondly, In terms of being objective in our approach to discover what is the purpose of sex, I must say this is a futile work. Nature being inanimate, it could not validate any objective reason for purpose of sex which then is given to it by the human being without its consultation subject to human understanding.
Even so within human understanding, an objective approach would want for evidence which would not support the theory that the sex is essentially for reproduction. Throughout history sex has been used for several purposes, expression of love, fulfilling the marital duty, a manipulating tool, an intimidating threat, reproduction, sexual gratification, violence and harassment, spiritual awakening, religious rituals and even as a currency are few examples among many others. Choosing one as the real purpose of sex is oversimplifying the complex nature.
Another way to look into it is to ask whether anything is unnatural at all? The human psyche itself is the product of nature. If natural selection has not eliminated homosexuality should we question the "naturality" of the way human beings are evolved? A better approach to it would be to try to understand how homosexuality has a part to play in human existence which may make us realize it is not the only reproduction that is responsible for our species continuous existence.
A homosexual relationship is real, in terms of existence, I will go back to my original stand if it exists it is natural just because it does not fulfill the expected notion of the purpose of relationship in direct way would not mean it serves no purpose at all. A Scientific approach would mean to look for evidence, and the existence of heterosexual relationship could not discredit the existence of homosexuality. They both exist, they both must have a purpose, in strictly scientific terms of course.
Should homosexual accept the label unnatural even when many negative connotations are involved in it? Do you think there would ever be an objective and scientific response of what is the purpose of sex? Is free will? and individual freedom enough to grant rights to an individual? Let me know what readers responses are to these questions.

Sabda Pramana for Science - The Nyayikas and Mimamsaks of Modern Day Science

For a layman, how can science be authoritative?

Few people today are in a position to investigate into the true nature of science. A layman is always a layman and most of them like to remain so. The question also arises when a scientist of different stream investigates about other streams (say a linguist about biology). What should he believe or better, whom should he believe? 

A better question would be, ‘is science based on verbal testimony?’ 

It eventually comes to verbal testimony, the first introduction to science comes to us by books and established courses of universities and schools. We cannot be much skeptical about them in our initial stage of learning. Afterward, this kind of learned verbal testimony takes a part of axioms which Mimasak would call ‘svatah pramanit’ or self-valid. ‘A point has no dimension’, ‘two parallel lines intersect at infinity’ etc. one cannot escape from verbal testimony, a better thing to do is to find trustworthy verbal testimony.

A scientist would never agree, for him science is empirical truths or facts discovered by a scientist and rendered into formulas. This is reminiscing of the claim that Veda is the compendium of empirical truths or facts seen by sages and rendered into mantras, again a Mimamsa viewpoint.

But there is another view, to explain their position on Shabda Paraman, Nyaya formulated the theory of ‘Word of Apta person’ or the words of a trustworthy person in the particular field in question. We often find the same argument with ‘scientific’ devotees. The cult of Tesla or of Einstein often takes up the monotheistic flavor just like the Nyayikas who eventually became a theistic Hindu school.

The mimasaka are not into human or superhuman. They never were. From the very beginning of prose part of Veda, the Hindu orthodoxy took up a very anti-theistic position. The Veda are eternal and just like the world are not created by some monster. Sabda Praman is not because of the character of Einstein et al which because of their human nature could be doubted but because of the theories itself.

Mimamsak Scientist would say, “Natural laws of science are eternal, the scientist just discovered them. The eternal laws could equally have manifested in mind of any john dick or harry. Such laws are then tested and validated by scrutiny. Unless falsified there is no reason to doubt the Sabda testimony of science.”

Nyayik Scientist would say, “Science can be learned from the appropriate person. The validity of the testimony of science rest on the validity of the scientist.”

What do you think is the better reason to believe in the verbal testimony of science?

Superstitionisation of Tradition

This is not even a word, superstitionisation, but it is happening. Let me give you an example.

Q. Why do we touch elder's feet?

A. When we touch elder's feet and he touches our head. This completes a circuit and positive energy flows from touched to toucher.

What is this? It is superstitionization of Indian tradition, in which a simple mark of Honor or respect, the touching of elder's feet is explained in scientific jargons having no proper scientific validity. So it changes a simple tradition of showing respect to a pseudo-science and is debunked in due time.

Why not a more traditional way of explaining it, saying it is just the way we do it. Why do we need to explain our Namaste, Pranam etc in such ridiculous way?

It would be difficult to debunk things which are done just for the sake of doing it. How would you debunk handshake or adab? But once it is explained away with neo-science it becomes falsifiable.

Naive Indians fall for that, filled with the inferiority complex. Not realizing that this way any tradition could be finished off easily.

What do you have to say about this?