Why is there so much opposition to homosexuality? Granted, the world has as a whole come a very long way since the days of Leviticus (even though many still ascribe to it), but there are still very many people who are opposed to homosexuality on various grounds.
This is by no means a comprehensive dissertation on the subject, but rather a few thoughts on some points that get raised, since Uganda has brought it to the forefront.
The one I hear most often is that homosexuality is unnatural, thus it must be wrong. Yet we have hundreds of examples where wild animals engage in homosexual and bisexual practices on a regular basis – arguably the most famous being the Bonobo.
But the problem with saying it's 'unnatural' reaches far deeper than the fact that animals do it, it's about what nature itself is. Nature (with regards to the biological) has no collective mind, it is just what emerged after aeons of slow selective pressure to survive. We build our laws around centuries of philosophy and debate, not just on what we see around us in nature. While I am all for homosexuality and do see it as natural, I don't think it being natural has any bearing on its validity or lack thereof.
Another argument against homosexuality is that of 'It's sinful!' This needs very little explaining, since 'sin' is most certainly not a scientifically valid concept, and thus not one I'm too concerned with. The same book that tells us to put to death homosexuals also commands that we cut social contact with people who have sex during a menstrual cycle, something which is so bizzare that I find it almost incomprehensible why any deity would concern themselves with such drivel.
The final point I wish to touch upon is that of homosexuals and AIDS. Sure, AIDS did emerge onto the world-stage as a disease infecting primarily gay and bisexual men, and it is still considered a risk factor for getting HIV. Now while some like to make it seem like this risk to gays is due to them being overly promiscuous, evidence points to it being considerably more complex than that.
Consider the fact that anal sex as a whole can increase HIV transmission, not just among homosexual men, by about ten fold as compared to vaginal-intercourse. The reason for this is three-fold: lubrication is not as thorough as it would be under vaginal-intercourse circumstances, the mucus membranes within the rectum are very thin and easily damaged by mechanical friction, and lastly there is possibly a larger concentration of CD4 carrying cells (the ones that usually get infected) in the rectal mucosa.
It is worth bearing in mind that not all homosexual men engage in anal sex, and many heterosexual couples do. Increased risk of getting HIV is hardly grounds for discrimination against homosexual people, since it's not exclusive to homosexuals and the increased risk of a disease is not a very good cause for discrimination (it would be about equivalent to criminalizing obesity).
So homosexuality is natural, though that's not really relevant to the discussion. It is only a sin if you believe in sin, in which case I sincerely hope you have no legislative authority. And sure, anal sex might give you HIV, but so could the regular kind.
Hatred of homosexuals is nothing more than a cultural norm that has been ingrained in people through religion and indoctrination, and as such it has no logical base in reality – and no place in law.