Not OP, but it’s kinda besides the point. Using Twitter for this makes it global by default.
I think it's much more likely that an American simply didn't bother to think that non-Americans would see the post.
My main point wasn’t that he was trying to make non Americans bad but rather I don’t believe his premise that he was disclosing his salary information for a greater good of helping minorities and disadvantaged people.
Again I support disclosing salary openly but disguising it as an act of social good sounds distasteful to me.
If you haven't considered this before, here's an article that covers some of how it can help: https://www.bustle.com/p/sharing-salary-information-at-work-...