Thork, if a gay couple adopts and properly raises a child that straight parents abandon, doesn't this make them very beneficial to society because they are covering for the fuck ups of irresponsible straight people? It's not only irrelevant to almost every debate to say gays don't (or can't) benefit society, it's just straight up wrong.
A weak point, seeing as more kids are adopted by heterosexual couples than homosexual.
Irrelevant. Just because there are heterosexual couples covering the mistakes of other heterosexual couples does not mean that homosexual couples can not also cover for the mistakes of heterosexual couples.
If a gay person adopts and properly raises a child then society as a whole and that child in particular are both benefited.
The point is that there are a lot more heterosexual couples available to adopt children. Even if every homosexual couple adopted children, their impact on the pool of unadopted children would still be less significant than all heterosexual adopters. You originally claimed that homosexuals are beneficial because they adopt children, however, adopting children is not exclusive to homosexuals. There aren't really any benefits a person provides solely by virtue of being gay.