For the religous person, the most popular reason for homosexuality being looked down upon was because the bible claimed that the act is a sin. Because the word sin is so ambiguous, I am adding Wikipedia's definition below.
QUOTE
Sin is a term used mainly in a religious context to describe an act that violates a moral code of conduct or the state of having committed such a violation. In monotheistic religions, the code of conduct is determined by God. Colloquially, any thought, word, or act considered immoral, shameful, harmful, or alienative might be termed "sinful".
A few of the other posts that may have been based from view points outside of religion claimed that homosexuality was a threat to the human race in terms of halting reproduction to the point of extinction.
Now I will take a moment to analyze the religous mindset that homosexuality is indeed a sin. Most christians accept that Jesus fulfilled the law of Moses, removing the need for animal sacrifices, an eye for an eye, and all of the other harsh laws of moral conduct that had existed until his time of teaching. Most biblical scholars will explain the mosaic law as the lower law, a law that was neccesary to prepare the Jews for the higher spiritual law that Jesus would teach. In essence, sin was redefined when Jesus fulfilled the law of Moses.
Outside of the religous view that homosexuality is wrong because it is a sin, what exactly is homosexuality? It is engaging in sexual conduct with the same sex, and to a further extent, having a long term relationship comparable to mariage.
Is pleasure evil?
Widipedia definition of evil:
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In religion and ethics, Evil refers to the "bad" aspects of the behaviour and reasoning of human beings —those which are deliberately void of conscience, and show a wanton penchant for destruction.
So pleasure is not evil so long as it does not rob a person of their conscience.
Wikipedia definition of pleasure:
QUOTE
Pleasure is a positive sensation, which by analogy to pain, can be physiologically described as either peripheral or central (euphoria). It is commonly conceptualized as somehow opposed to pain, though it has received much less scientific attention.
What do we call a person that causes another person pain? Evil, sadistic, callous, and macabre are a few names that come to mind. Per wikipedia, pleasure is considered the opposite of pain. So in essence, someone that indulges in pleasure with another person is representing all that is good.
How would you define a person that believed in surpressing the feeling of pleasure, and beleived that they needed others to follow their lead in surpressing pleasure? I would regard the chance for pleasure being stolen away as an act of pain. What kind of people like to cause pain? Evil, sadistc, callous, and macabre people.
Rather than attack religions as inconsistant and hypocrytical, I am going to suggest a revision of what they consider sin. It has been done twice that we know of in the bible. Once when Moses defined it, and again when Jesus redefined it. It is not something that cannot be done. In the end, it would be a healing measure that would unite people in new understanding and acceptance.
For those that would argue that redefining sin would open pandora's box to allowing any kind of immoral act to be committed, I will reply in advance. Human's have the ability for intelligent thought. We know the difference between right and wrong. The reason homosexuality is such a heated subject is because so many people realize that repressing it is wrong. The reason you do not see a large crowd of people advocating pedophilia or animal sex is because people know that these things are wrong. People do not know that homosexuality is wrong; the only argument that they have against it is that their bible has said it is sin.
I won't bother explaining that homosexuality is not ever going to be a threat to breeding ourselves out of existance. Plenty of man made folly will send the human race into impotence long before homosexuality would ever even remotely come close to bringing about the end of our race.