In alot of the major religions being gay is a sin. Now , this makes zero sense to me , because first off there is no reason and second gays are born that way , so did God create them just so they can burn in hell ? I have heard the reason is that gay sex spreads Diseases , but so does heterosexual sex. So why do you punish people for the way they were born ?
In my view, the condemnation stems from a time where group survival was the number one priority for human beings. Of course, homosexual individuals not procreating, the remainder of a group will perceive them as a burden for the group's long term strategy (the burden being mouths to share food with but genes not passed on). The stigma can be explained - I believe - with this, and it is then reflected in various religions that came to be later. Back then, it did make sense, but then again many other incredibly cruel things did also make sense and the world was a much, much more gloomy place.
Nowadays, the urgency of species survival is less intense (though it is still there, most are just willingly ignorant of it), so those of us who are born to this age, such as myself, take a tolerant and understanding view on these people, who by the way have stopped being a burden and who can contribute to the group in other ways. For example, a genius researcher who happens to be a gay/bisexual/transgender will be more crucial for human survival than ten straight lumberjacks. Of course, the reverse is also true, although I might have trouble finding ten gay lumberjacks.
In any case, that's how I'd figure it all out.