the examples I read this weekend were that people don't follow their genetic heritage necessarily so it wasn't any different than other things we do that are supposedly part of our genetic heritage. One guy said, "well, genetically, I'm supposed to be promiscuous, but I don't act on it." Another said something about being omnivores and capable of eating meat, just not acting on it for moral reasons. blah blah.
in the black community, research has shown that they are willing to support civil rights elsewise, just _not_ marriage. as is pointed out in the article below, the reasons are complicated, but I suspect the reason why black heterosexism is higher than typical levels of heterosexism among whites and latinos has to do with desire for cultural assimilation: being heteronormative with a vengeance, in other words, to *prove* to whites that you're just like them. As the VV author says, black folks have unfortunately become *more* bigoted than whites on some issues. (Which is why I have said that my observance of issues at work is a _class_ issue: both the hatred of poor people and the hatred of homos.)
plus, you're missing the big issue among black activists: the objection to the comparison is sometimes about feeling that the discrimination isn't the same so it's offensive for gays to compare their trivial issues to blacks' struggles. the more radical left approach is to object because it is a form of appropriation.
see http://www.villagevoice.com/2004-05-18/news/whose-dream/1
and
http://www.blackcommentator.com/110/110_fr_gay_civil_rights.html
>
> That's how the belief system works, isn't it? Not many people condemn
> homosexuals for having sexual desires for others of the same sex; they are
> condemned for acting out on them. I never thought of this before but
> there's also the idea here that you can be taught to be gay.
>