> in your American culture there are only two ways of life

That might be the culture I come from, but it is not my culture, and I do not subscribe to it, claim responsibility for it, or claim ownership of it.

Then again, there's not a lot of people in my culture, they're pretty spread out, and it's hard to get them together in one place to do our thing, soooo.

America is a lot of different cultures. Most places are. https://tvtropes.org/pmwiki/pmwiki.php/Main/PlanetOfHats

Try to elaborate on why they are against gays marrying without the reasoning sounding homophobic.

It is a motte and bailey argument, most people agree with gays having access to legal marriage, the contentious part is religious marriage. Should we force preachers who don't believe that homosexuality is kosher to wed gay couples? A lot of people don't think so, and then they say they are against gay marriage even though they would be fine with legalizing them getting a legal marriage.

For example, do you think that we should force Muslim Imams to wed gay couples? I believe that it would be a fairly controversial topic even in left-wing circles.

The idea that gays are going around forcing religious people to marry them against their will is contrived and demonizing to gay people. Nobody forces someone to officiate their marriage. The question of gay marriage is entirely about the widespread legal ban on gay marriage and whether that is/was justified.