I'm not sure what you mean by "the difference", but yes I do agree. We all treat people in certain ways depending on how they look and their overall demeanour - anyone who says they don't is either dishonest or deluded.
I came into a Severn lock single-handed a couple of weeks ago (can’t remember which one), and there were a group of 5 or 6 youths, at the other end with one fishing rod between them. They were messing about chucking things into the other end of the lock, throwing things into the river, smoking dope and generally acting like they didn't care what anyone else thought. I asked the only other bloke there who was watching me go through the lock if he wouldn't mind waiting around until I had exited and I nodded towards the youths. He knew exactly what I was talking about. I said to him, I don't like pre-judging people but they don't really help themselves by looking and acting the way they do.
If I dress up as a vicar and stand around a church, it’s likely I will be treated as vicar by passersby who may ask me about the history of the building, etc. If I dress up as a policeman and walk down the road I wouldn't be surprised if members of the public responded to me as if I were a policeman - be that positive or negative. I could wear a white coat and carry a stethoscope through a hospital and someone would probably treat me as if I were a doctor. My point is that I wouldn’t blame those who were fooled by my attire for making those mistakes.
Likewise if people dress up as a chavs or a gangstas it’s generally because that’s the way they wish to be perceived. They may not be overtly seeking violence, but I’m afraid the idea is often to intimidate others. If people don't want to be judged negatively then perhaps they should think about how they look and the way they behave, rather than blaming others for what are perfectly natural perceptions and reactions.