[Certhas]

You complained about their lack of proof first.

I have given arguments [1] why I think their claim is plausible. You haven't given any why you think it's wrong (other than a generic "why should it be true?", which is nothing if not demanding proof from them).

[1] The mentioned communities are overrepresented in any risk category, from drug addiction, to HIV, to homelessness (the sole exception I know of would be suicide). They tend to be more overrepresented when marginalisation dimensioons intersect, as they do here.