if white is being used this generically then romani should be listed as white and arab should be middle eastern and tibetan asian if not lumping both as asian.
Romani are actually a group of Indians who traveled up to Europe I believe over 1000 years ago, according to recent dna testing. The history of why the group migrated is lost to time. After so many generations a few white people got in there certainly, but originally people thought they were egyptian.
white is thrown around but its a very imprecisely defined thing.
The meme isn't about what kinds of people are called white. It's about non-white characters being replaced with white characters, and no one uttering a peep. Then a mermaid is re-imagined as black and everyone loses their shit.
(another possibility is that I am not understanding your point)