this is half in response to your last post, and just to let you know, im not religious, and i do support gay marriage, im just defending people who do not support it.
anyways, i dont think the MLK argument relates very well to the gay marriage issue. Im all about equality and all that, but not to the point where it interferes with common sense. between races, yeah, we are all equal, and should all be treated equally. between men and women? well we arent equal, men and women are very different in a lot of ways, physically and mentally. men do certain things better than women, and women do certain things better than men, and i think a society should treat each sex in a way to reflect that, doesnt necessarily mean you have to treat one better or worse, just differently. and sure there are definitely the occasional man or woman who happens to be able to do the other sex's job just as well, and we should certainly be open to that.
so before i get off topic, i think the marriage issue is definitely pretty gender related, we have gender specific laws and rights, and gender specific cultural norms. and marriage is definitely all about what genders CAN get married. in our society, marriage has always been between a man and a woman, not only because religion plays a big part in our society, but because it makes sense, you need a relationship between a man and a woman to have babies, continue the family genes and name, and continue humanity. thats long been our reasoning in OUR culture for defining marriage as between a man and a woman, its a human nature, gender related practice. when you throw in two dudes, it doesnt really work/apply, its a different kind of union that only partly applies to what we have always considered marriage. even as a gay marriage supporter, i still dont really "get" gay marriage, i still view marriage as a man and woman thing, i just happen to be ok with it if two dudes get married.
anyway i understand cultural norms change, sometimes for the better and sometimes for the worse. but cultural norms are definitely necessary, and important, they are part of what defines our rights and laws. and im glad that we have people on both sides to change them when they need to change, and stop them from changing just for the sake of keeping up with the times.