I covered stereotyping quite a bit in my university studies (I studied marketing) and the broad consensus was that stereotyping is a useful tool because it saves time.
As much as we "should" judge people on the nuance of who they are and their individual character, we are presented with an overwhelming amount of information and we need to make a quick decision.
This is why I've held the opinion for a while now that it's good to dress well. People are going to judge you and put a value on your time based on how you present yourself. Nothing wrong with maximizing your odds of that going well.
There is something wrong with "dressing for success" -- it makes it easier for frauds to get jobs from talented people. but it's a locally optimal decision, and it's not your fault that people judge your work by your clothes, so it's defensible even though wrong as a broader social context.
As much as we "should" judge people on the nuance of who they are and their individual character, we are presented with an overwhelming amount of information and we need to make a quick decision.
This is why I've held the opinion for a while now that it's good to dress well. People are going to judge you and put a value on your time based on how you present yourself. Nothing wrong with maximizing your odds of that going well.