Okay, so someone needs to educate me

I will own being as white privileged as it is possible for a female person to be, so the follow post and its addendum puzzled me:
"

Let me make it clear that white people should never under any circumstance make or engage in white jokes. No matter what your intent is, you have effectively communicated that you think you’re different from other white people and have earned the right to join poc in the one thing we have to make light of our daily experiences with white supremacy. You look like an ass when you do it.

yep. you’re taking power away from it, which means you’re taking power away from us. you’re distancing yourself from your white privilege- you feel exempt from putting in the hardest kind of anti-racist work- processing your own internalized racism & white supremacy. so who does this help? no one, but you. it is selfish and damaging"

First reaction: "Isn't cultural appropriation sort of our thing?"
Second reaction: "Wait, white people do this?"
(My brain has a lot of parts)
Third reaction: "Everyone chill until we find out what sort of jokes we're talking about here."

So...what sorts of japery am I avoiding in order to not be a supremacist jackass?