The thing is, most non-Americans dont connect master with slavery at all. In the same way we wouldnt connect cotton with slavery. It was a term used within the context of slavery, but wasnt created _for_ slavery. In fact, it long predates african-american slavery:

_late Old English mægester "a man having control or authority over a place; a teacher or tutor of children," from Latin magister (n.) "chief, head, director, teacher"_

So if we dislike the user of master, do we ban whip? Or any other term negatively associated with slavery that actually predates it? I think the actual answer is contextual, and in the context of git, there is no relation to slavery whatsoever for most of the worlds populace