NOUN : A person who pretends to enjoy racist jokes told by their friends (peer pressure), while actually not approving of such slander, and not buying in to the stereotypes often exploited in such jokes.

Formed by a combination of 'race' and 'imitator', the word racitator can also be used in the case of theoretically any offensive joke, including : Sexist, nationalist, anti-gay, anti-Semetic, and so on.