You're taking it very literal here, from my perspective it doesn't mean "literally treat others according to your preferences", it means "treat others with the same kind of consideration you'd offer yourself". It's like: wouldn't you want people to treat as best they can you in a way that aligns with your needs and values? So treat them in a way that aligns with their needs and values. I think it also implies that people would have respect and care for themselves, but that's not always the case in reality.

It's really like the semantics of "walk this way".