This is not true. We live in a society with rules and laws on how to treat people. If the law says someone goes to prison for murder then "we" as a society have agreed to this. If everyone lived by different laws, we'd be in chaos.
You are saying people are not individuals with their own preferences?
Sure you can draw mental or geographical lines around people. And then try to apply laws to them.
But at the end of the day there are still people in those lines choosing to follow, or not follow the laws in various ways. And people treating people differently even while following those laws.
Only when these rules come into conflict. People can have different preferences, include preferences about with whom to associate or not. Allowing for that is a necessity for living in a free society.
