You could extend that idea to debating in general. I don't think internet debate sites suffer from this problem anymore than any other platforms for debate.
If that's a statistic, then I have a number of arguments against it. Although my main counter argument to your point is that even if this were true, how does this relate to the stance against homosexuals being allowed to adopt?
Your personal disgust at homosexuality doesn't relate to the argument of gay people being allowed to adopt, whilst your view that homosexuality is a mental problem is simply wrong. I'd like to know how you define mental problems.