Talk about being oversensitive.
Can't take a joke, can you?
Racialist? When did Greek become a race?
While there's no scholarly consensus on whether or not racism per se extends to groups other than distinct races, we're not scholars. I believe any form of derogatory ethnic stereotyping would fall under "racism" as far this forum's rules are concerned and as a moderator, our judgements on the guidelines we have are final. It's says so in the T&C.
So, consider this a friendly warning. Joke or not, it's not cool and not welcome.