I don't see why it would be that much of a shock. Racism isn't entirely the domain of white Americans. Ask a Japanese nationalist what he thinks of Koreans if you need evidence.
The only people who say that shit are dumb teenagers who just discovered social justice yesterday. They're hardly indicative of the Internet as a whole.
And as a white guy I usually sigh and think "they do be that way" because it's usually pointing out a large group of actual shitty people who also happen to be white. It's not like they are rare, lol.