Meh. I can understand it to a degree. I have no sexual attraction nor interest in seeing two lesbians have sex with each other. Hell, I have no interest in seeing a straight couple have sex with each other.
But I wouldn't have to "turn my head" if it came on and I certainly wouldn't have a physiological reaction to it, like the poster you quoted said he would have. That seems a little ridiculous to me. Seeing two lesbians in a Bioware romance scene wouldn't be the end of the world for me. I have little concern for people who have such over-the-top reactions to the very idea of two guys doing some dry humping (really the extent of what you see in Bioware sex scenes) and maybe seeing a guy's ass.
Don't get me wrong, I'm not prone to recoil at the sight of anyone being intimate. Sure depending on the time and place it might make me uncomfortable but I'd just remove myself from the situation if it seemed like it was going to continue and/or escalate. I'm just saying I get some people (particularly straight guys) aren't able to cope as well as others might. Considering how ingrained it is for men to be masculine and eschew any and all things even remotely considered feminine, it's not surprising that when confronted with males being intimate with each other, heterosexual males have a negative reaction. I'm not saying that it's ok. I'm just saying I understand why it happens.
Consider that women are far less reactive to such things. I believe that's because society puts different types of pressures on females than males but in many ways females are a bit more free to be themselves. Sure the whole cavalcade of "pink things", "dresses" and "dolls" are foisted upon girls from day one, but when females deviate from things defined as strictly feminine it isn't as big a deal for them as it is for a male.
If a boy is seen playing with a doll, even if its say a Ken doll, he's ostracized mercilessly by his peers and many times even by family. On the other hand if a girl decides she wants to play with cars and robots rather than dolls and make up, it's not see as that big a deal. Sure, some of her peers may not "get it" but it doesn't frequently result in her becoming a social pariah for the rest of her young adult life. But you can be sure if that boy who played with a doll in front of his peers remains in that community, that incident will haunt him until he finally gets out of that community (typically after high school). I speak from personal experience on that one.
Not every person has the fortitude to live as themselves rather than what society says their "supposed to be", and in many cases if confronted with things that challenge the expectations they were raised with, straight males react defensively to anything that might challenge their perceived masculinity.
Cause obviously if you're straight and two guys holding hands doesn't bother you then there must be something wrong with you! /sarcasm