Chinese don't like it, because it damages the ability of the family to pass on the family name and create the next generation of sons. Also, originally, the gentiles had gay sex in the temples.
I live in China and I asked one of my Chinese friends why gay marriage is illegal in China. He came up with many reasons, all of them stupid and illogical.
He also said that gays shouldn't marry because they can't carry on the family line. That argument is flawed in so many ways. First, your family is not going to die out. You are related to every living thing on the planet, separated by time and evolution. Even among other humans, you have millions of living relatives within just a few generations.
I said that gay couples can adopt, and still carry on the family name. He said that isn't a real family. Of course that pissed me off because I have two adopted daughters. Who is he to tell me I don't have a real
I also pointed out that if you're going to forbid anyone who can't procreate to marry and limit marriage to only "real families" you should also ban adoption, and marriage between elderly people past child-bearing age, infertile men and women, and anyone with an injury or disability that prevents intercourse.
Also, someone who doesn't marry still won't carry on the family line regardless, so banning gay marriage doesn't fix the problem.
He said gays shouldn't raise children because a child should have both male and female role models. I said that by that logic we should take babies away from single parents. Also, unless a child is raised in a vacuum, the will be exposed to both male and female role models in their family, community, and culture. A child raised with two daddies will still understand the role of a mommy even if he doesn't have one.
At one point he actually said that gay marriage is illegal because if gay marriage were legal, the human race would die out. I tried to explain that allowing gays to marry doesn't mean everyone would have to be gay, but he didn't seem to get it.
He said that if gays have children, their children will be gay. I explained that all gay children are the result of heterosexual sex.
In the end he admitted that gay people just make him uncomfortable, and he supports the ban simply because he doesn't like them.