Think about it that you are talking about minorities, especially when it comes to LGBT people. Minorities are smaller, thus it's harder for them do defend. That's why some bigger entinty, like govt comes in and protects this minority.
You say you don't support gay marriage. May I ask why? Why is it different than non-gay marriage? People just want to love their loved ones. Your career would be over because you are sorting people for those better and those worse. I don't want to remind you about the most famous movement that was segregating others.
I was on (we don't call it Pride March here) Equality March in Białystok last year. Straight people (I should say animals, but I don't want to harm animals saying that) were throwing stones, petards, tomatoes, bottle etc. at us. We were mercilessily attacked by conservative people. I am saiyng that to ask you about not generalizing, not every gay/straight march is the same.
edit:
typos