Why do some women treat guys they don't find attractive rudely even when he hasn't done anything wrong?

This can be anything from the women giving odd looks of disgust to him when she glances at him, to not even looking at him when he asks for something or places a order, some women may hold the door open for anyone else but him, and even when walking past fast to try to avoid him she nearly pushes him out the way or runs over him. I seen this happen to one of the guys I work with from multiple women and not just one time.
It's almost like some reason you have to look a certain way for some women to even treat you decently. Do you know why that is?
Why do some women treat guys they don't find attractive rudely even when he hasn't done anything wrong?
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