Never in my life have I associated git or its default branch name with American slavery. I would be shocked if a single black programmer in the world had considered before last year that it might be offensive. I haven't discussed the issue with any black friends or family, but it's just such an odd leap to make even if the claim about its etymology is potentially correct.
Of course, if even a minority of black programmers were or are offended, it's not my place as a non-black person to tell them they're wrong. I'll happily rename all my branches, update all my code that references master, rename all "master" test environments/hostnames, and update the gitconfig on all my machines, if credible surveys come out showing that a statistically significant number of black programmers genuinely consider master branches offensive.
Until then, I'm not going to do free labor to back up what so far appears to be an ill-conceived PR stunt on GitHub/Microsoft's part. The only arguments I've seen in favor of renaming master have been from white people appealing to technicalities/etymology, as if solving a puzzle to prove whether it should be offensive according to some logic, rather than any kind of appeal to the feelings of actual humans.
"Robotic wokeness" is a nice term to describe this phenomenon. I'm all for Black Lives Matter and correcting genuine injustices, but it's harmful to everyone when private interests artificially manufacture outrage and social justice causes solely for their own benefits.