I'd also posit that the jokes just aren't racist. Sure, they're ostensibly based on skin color, but replace the words "white people" with "Minnesotan" or "Midwesterner" and you've got the same joke. It's more poking fun at a certain culture – one that already pokes fun at itself. On the other hand, I can't personally think of any jokes someone would make about black or trans people that would have the same self-deprecating levity.

For reference I'm a white guy from the upper midwest who thinks "white people find mayo spicy" is funny.