"I am right because my claim is factually correct. My claim is that I do not know whether harm is the exception or the rule. The person here claiming to have a definitive answer to that question is you, not me. My claim is factually correct, I do not have the evidence to conclude one way or the other."

Dakota can correct me if I am wrong but from what I can tell he is saying that not all sex is harmful for boys but MOST of it is and since most of it is harmful AND you can have a beneficial relationship without it then you should not have sex with a boy.

ie he says not all sex is harmful but enough is to make him refrain from doing it.

I am not saying I agree or disagree with him or his reasoning but that I believe that your summation of his argument is wrong.