Uppity, I understand what you are saying and you are right that you cannot tell the difference by looking at someone or even knowing them for a short period of time. The most prominent members of society are abusers. My mother is a church-goer, a foster carer and has adopted 2 mixed race children, to others she is a saint. To me she is a controlling abusive neglectful and selfish woman. I can now see psychological traits in here that others cannot, because she puts on a face to them but in private she was and is very different.
But I try to steer away from including personal experiences because there is always someone with an opposing experience that contradicts what you are trying to say.
So me saying that I think rapists do share some common characteristics is not the same as me saying that you can tell a rapist a mile off. Not at all. The whole reason for profiling is to try and identify traits to help police investigations, to help support groups, to help raise awareness, to help prevention.