In other words, being able to choose to disregard the concept of race is itself an expression of privilege.

In a perfect world where everybody had that attitude, it would be the right attitude to have. But as long as some people continue to not only regard it but also use it as a tool to discriminate and oppress, their victims do not have a choice but to regard it also. To tell minorities they shouldn’t care about race is to deny them the means to describe how they’ve been wronged.