Oh that's racist is a call created by Siva in early 2010. It is primarily called when a comment such as 'Gee, the sky looks a bit dark today' or 'No thanks, I don't like dark chocolate' is made. It is called in a loud voice starting deep and ending high.
It can now be combatted with the call, 'No, it's cultural'.
The call is now very rarely spoken as Siva has come to accept that sometimes people are unintentionally racist, just don't happen to like all dark things.