I also hear what you're saying, and I agree with your point that a black person wouldn't have come up with master/slave. That said, I've also worked closely with black developers and while I don't want to make assumptions, it's really hard for me imagine them being offended by something like this. It's more like a parody of what a white person who has never spent any time with black people thinks a black person would be offended by.

But regardless, it's not that I'm so stuck on using this specific term. I don't care that much, and primary/secondary is fine, as you say. My point is that many people and groups will have more-or-less equally valid complaints about countless other words and terms, and I don't think attempting to excise all of them from our language is a helpful or productive path to go down. As many anecdotes in this thread have demonstrated, it's not "just a swing" or just a single idiom. It's already starting to snowball into a pretty long list.