[bb88]

A quick google search on the origin of the word master comes up with this (and in fact, I don't know why you didn't search this originally).

"Master comes from the Latin adverb magis (“more”). It first appeared in English over a thousand years ago, referring to people who had authority over others, whether as rulers, employers, teachers, or fathers."

I would imagine slaves and slave owners would be in that list as well.

I'm not saying that "master" is always racist, but in certain cases, it seems pretty clear -- as in the Master/Slave J/K flip flop. The example given "master bathroom" surely seems like it could have racist connotations.