There are a lot of things that make up the...construct? of race. Class and privilege and whatnot are all a part of it and that's where things get complicated about it. I *wish* that there were a clear answer, but sadly there's not and as mosca says below, the complications do make it so that the assumption of "oh, this person is white because they're not obviously something else" is easier and less scary to make. So it's understandable. It also just *really* frustrating.

So I occasionally make these posts and then I go back to being quiet about it for a while and things (hopefully) get better. I dunno.