So many providers are No brothers allowed whats the deal

I probably know the answer to this question as i know how a vast majority of us behave in public i cant even imagine what happens in a private setting. My only beef is that we have all been black listed just because a few jack asses have ruined things. I would think it would be obvious over the phone what type of guy you might be dealing with. Now this is all my assumption it might be something else going on if so could someone please enlighten me.

The search button can enlighten you. This topic has been beat the hell up, do some research.