@aral
Well, I understand the feeling, but I'm a "get confortable being inconfortable" kind of guy when justified. In this specific issue, ( french native, still learning English and French) I don't think "mastery" implies being a teacher, boss or trainer. ( May be wrong) so in that case, I believe there is room for nuance in the term.
Slave/master: bad
Master-expert : nice
And I'm fond of keeping nuance in the world.
@aral
I loved that many projects spent a comparable time putting "Black lives matter" banners on their homepages at the time helping spread the word. This, seemed to me like a more productive and frankly, clearer way to address the issue.