Thinking in terms of the US constitution and the laws built on top if it, ostracization by the government is forbidden and ostracization by private citizens and entities is not.
> ostracization by the government is forbidden and ostracization by private citizens and entities is not.
So its fine to fire all black people to ostracize them? No, of course not, so no you are wrong here, there are more limitations than that, people have rights protecting them from a lot of ostracism.
> This works because people can choose to not be jerks, but they can't choose to not be black.
What if they could? People can change gender identity nowadays, and it's not outside the realm of possibility that people could change their phenotypical characteristics (transracialism is a hotly debated topic).