Ok, this just has to be corrected:
Your first problem is assuming "normal" has any meaning besides in the statistical sense. "Normal" simply defines the frequency of a characteristic, nothing more. It says nothing about the morality, survival benefits, desirability, etc. The only thing it tells you is "characteristic X has a frequency Y that is above the arbitrary threshold frequency Z allowing me to approximate it as typical of that group".
But in any case, your argument about homosexuality being removed from the population is fundamentally flawed, for two reasons:
1) The most obvious is that sexual preferences do not keep an organism from reproducing. People (and animals, though it's harder to tell their preferences) can and do have sex with people they are not attracted to, for whatever reasons. Just look at half of the republican party... they have perfectly "normal" marriages and children, and then go foot-tapping in every bathroom they can find.
Even if you have no attraction to the opposite sex, the physical act of reproduction is easy. And it gets even easier if you don't see things in black and white... if you are 90% attracted to your own sex, 10% to the opposite, it's trivially easy to take a less-appealing partner, make some offspring, and then go back to whatever partner you really want.
In fact, it could be argued that most people do this. The vast majority of human sex is done for purposes other than reproduction (note that this is a fundamental difference from most other species... humans are able to have children only at specific times, but show no external signs of this potential, the result being a lot of "wasted" sex).
Since the survival of our genes is clearly not at stake for 99% of our sex acts, what difference does it make (from a biological perspective) if, assuming you still do the 1%, the other 99% are with members of your own sex?
2) You assume that there is a single genetic factor for homosexuality, with no other effects tied to it. If you drop this assumption, it is easy to see that a gene influencing homosexuality could have other benefits that outweigh the loss in reproductive desire. And it's even clearer if you consider the first point... in fact, it would be perfectly plausible to have a gene with 90% homosexual attraction as a side effect. If the gene's other effects are good, the 10% desire (or social pressure to mate, etc) can allow it to be passed on.
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As for the rest of the thread, I'm too lazy to dig through it and pick out specific points to argue. But it sounds like people are getting way too close to the idea of preemptive justice. And this is entirely wrong, for very good reasons. Just think about it, and this should become obvious:
How many of you have ever thought of killing someone? Some one cuts you off in traffic and you have a brief image taking a sledgehammer to their head as you make your obscene gestures. Or your wife/husband cheats on you, and you just wish you could kill the other man/woman. Or for a lesser offense, how many of you have thought something like "wow that's a nice car... if only he'd left the keys in the door...."? Etc.
By the standards some of you are proposing, you should all be thrown in jail, or at least locked in some mental hospital for treatment. After all, killing someone is a far worse crime by any sane moral standard. And in both cases, there's no action, only thoughts. So why is one case of preemptive justice acceptable, while the others aren't?
