Well that is a good way to get someone's attention.
"I resent the idea that homosexuality is some condition that is the ultimate result of some less-than-ideal condition in the womb or the environment or my genes or the function of my brain, or whatever."
When you use 'less-than-ideal' here you're implying here that those who think sexual preference is not a choice also think that homosexuality is less than ideal. I believe there are far fewer people who feel that way than those who don't. Also this is not a great way to start convincing people of your case.
"What if I just choose to suck cock? What if I just like dick better than pussy? What if, in an absurd expression of the very kind of macho anti-feminism endemic to video game culture, I just prefer to get off with guys rather than ladies?"
First off, getting off with dudes would not be an expression of the 'macho' attitude that plagues video games. Hangin' out with dudes, drinkin' beer with dudes, playin' sports with dudes, macho. Gettin' off with dudes, not macho. Also, the people who really make up video game culture, the sort of people who sign up for a forum and discuss them, usually find that macho stuff distasteful, but that's a different topic.
Back on topic, in my experience most people will tell you they did not choose to be attracted to one sex or another. I mean MOST. Like, almost ALL people. And not just sexual orientation but one's preferences in general. Actually you are the first person I've ever heard claim they got to choose what they like. That doesn't mean I don't believe you but you have to admit it does seem to lend itself to the idea that you are simply confused about what you like and what role you may or may not have had in determining it.
"I mean, it's not as if my sexual history with women is nil. And it's not as if there aren't things about it I don't appreciate. But I dunno, being queer as fuck is just tons more fun."
What do you find fun about it? The sorts of things I think of would be acting the stereotypical, flamboyant gay man. I'm talking bright, fitted, outrageous clothing, an extroverted, in your face, fear nothing attitude, and nothing but cheers and smiles forever. I can see how this could be fun. This has nothing to do with your sexual orientation, however. You could do all of this, with or without all your gay friends, and not be gay. So what was it that made you choose to be gay? Could you choose to be straight later, if you wanted?
"And attractive men tend to be not near as inaccessible as attractive women. The odds are simply more favorable. As often as I'm approached by an attractive woman at these clubs (as they've started flocking here to avoid the straight guys, anyway) I might already have been approached by three men who are just as if not more attractive, and more sexually versatile."
So part of why you chose to be gay is because the way you act tends to attract men instead of women? Practical, I suppose. If only I could choose who to love in a similar fashion. Are there any other reasons you chose gay?
"Maybe that makes me a "******," and I'm sure a lot of people are just going to say "Dude but you're bisexual that's just science!!" but I'm being practical here. If the inevitable conclusion of this preference is that I'm likely going to find a guy and want to settle down with him, or run a business with him, or live with him, or do any of the things casual partners who might become serious lovers do, why should I be denied any those legal rights simply because I preferred not to do it with any attractive lady?"
Your first sentence doesn't really have anything to do with the second. In your first sentence you propose an argument against yours, one that has popped up many times already, but then you only address it by saying "I'm being practical here." and leaving it at that. Those of us who didn't choose to be the way we are didn't have a chance to be practical. This doesn't make the argument any less valid and really doesn't help your case.
As for your second sentence, I think most of us here are in agreement. As was already said, you're kind of preaching to the choir here, not that you could really know we were in the choir until you started preaching. There are some people who might benefit from hearing you, but they aren't going to hear from here.
"Many people are for these rights, but they seem to be so only because a heterosexual relationship simply isn't manageable because of my genes, or the function of my brain, or my mother's diet while I was in the womb, or whatever."
I believe you're wrong here, but I don't have any numbers to back that up, just my experience. Most people I encounter online and in real life believe gays should have those rights just because they are people. I am just as put off by those who support equal rights because 'it's not their fault' as I am by those who don't support equal rights at all. Like I said though, I believe we're talking about a small minority here.
"These same people will decry conversion camps, but these very camps are encouraged by the line of reasoning that homosexuality is a condition arising from some to-be-discovered factors. Thinking of homosexuality as a condition, and not something a reasonable, rational, adult person might choose to engage in, is the mindset that encourages people to "cure" and to "fix.""
'One's preferences are not determined by choice' and 'homosexuality is wrong and should be fixed' are completely separate ideas. You attached the word 'condition' to the former idea (essentially 'One's condition is not determined by choice') and that word has a negative connotation to it. It implies something is wrong, something that could be fixed or cured. When you attach that word to the idea, you are attaching 'homosexuality is wrong and should be fixed' as well.
"The religious right argue that homosexuality is a "choice," and when public opinion was strongest against homosexuality it was certainly beneficial to point discover and highlight some of the possible origins for same-sex sexual attraction. Biology certainly does have a significant effect on anyone's taste for anything- but it can't and shouldn't be used to explain every single possible instance of same-sex sexual expression, which certainly goes well beyond and public and avowed homosexuals such as myself."
Why shouldn't biology explain everyone's preferences? That's like saying physics shouldn't explain every instance of movement. Part of what science is about is discovering universal truths. Sure, sometimes we're wrong and sometimes there are exceptions (looking at you, photons), but that's only after evidence to the contrary is found. You haven't given anything other than your own word that it does not apply to you. You can imagine why I am not likely to believe you.
"Shouldn't we just accept that gay sex is just, itself, great? Not for everybody, certainly. Wouldn't give cashews to someone with a peanut allergy. But in general, among whoever's doing it, gay sex is pretty awesome. And ought not be culturally discouraged or legally discriminated against in any way."
People shouldn't agree gay sex is awesome for the same reason people shouldn't agree apples are better than oranges; Variety is the spice of life. You're just going to have to accept that some people will disagree with you on this one. As for legal discrimination, I think we're all on board on that one, even if it is only tangentially related to the idea of preference being a choice.
Sorry for the TLDR; My thanks to anyone who reads it all!