because that's not how people work. you are arguing form an impossible ideal.

you yourself incessantly discriminate people based on their appearances. the point is to prevent people from those discriminations institutionally.

every single day you are dismissing or admiring people based on how they look, they speak, etc. and your 'reasonable' for these things is wildly different than somebody else's. human beings are not capable individually of the levels of self-awarenesss you are presuming exist, even in yourself.

the laws are largely to prevent systematic and institutional discrimination, individual human beings will always be discriminatory. A individual person hiring at a large org can still discriminate, but the institution itself can't because legally if there is a pattern of multiple discriminatory practices that can be actioned against.