Mr Marcus and Marc Wallice trasmitted stds to some pornstars, I think that was the case of Tony Tedeshi too. Alex Gonz, Ramon Nomar and Karlo Karrera because their acting is average and because in their scenes I think there is no chemistry. Max Hardcore because he has been in prison and was very brutal and very degrading against women. Carlos Lagonzilla because he is batshit insane and Sean Michaels because he looks like a thug.
I agreed with most of your post except your racist comment about Sean Michaels. First, he doesn't look like a thug. Secondly, being black doesn't make you a thug. Thirdly, he is never given the thug character/role in films.