Should I apologize for something I didn't mean to do?

My friend’s ‘boyfriend’ or whatever they are to each other, has his Facebook wall flooded with a bunch of Asian girls flirting with him. My friend says that he makes fun of all those girls who are mostly Asian want him and he makes fun of how needy they are to him.

I thought it’d be funny if i posted on his wall “Hey talk to me, me love white boy!” since I’m Asian but don’t fit the stereotype. My friend said I should do it and he’d find it hilarious. I did….and later he ended up calling me a self hating, hater, that’s really bitter!

I really meant it as a joke and he INSULTED me! I told him he should have told me if it was offensive but name-calling was really disrespectful and immature. My friend told him he was being a jerk and so he agreed he was overreacting but he never told me sorry.

I honestly thought he’d get a laugh out of it because he made fun of them.