"It seems statistically improbable that I as a white person would receive so many microaggressions that have nothing to do with race, yet every microaggression that any given Black person receives must be about race. Are they never judged for anything else?"

Well, of course we are judged for other things, but that doesn't mean question black people for saying that what they just went through with someone was racially motivated. Plus, none of us think that we can't be judged for other things. At least, none of us with common sense, there are idiots in every group of people.

I would be fine with this if you brought up a specific situation people were saying was racially motivated and said it wasn't because of whatever, but this just sounds like you want to defend other white people for some reason. You're literally just saying:

"Hey, person of color, who has experiences I could not imagine going through! Explain to me why you think someone was being racist to you. Maybe they weren't. How do you know people are racist to you? I know I wasn't there, but you seem to think this was racist, and I can't understand why, so it probably wasn't and you're overreacting."

The title sounded condescending enough, and all you did was dig yourself deeper.