Should be master renamed to mainline due to moral conflicts?
Does the word master in git branch name really evoke slavery for native English speakers?
No. Example: “Master” chef.
Do these words really convey the sense of maleness?
No. Example: A “master” chef could be a male or a female.
This is my perception as a native speaker of English at my age (45) in the context of a software development community. The request to change this word seems to arise from the grievance culture, which universalizes the semantic domains of certain buzzwords across contexts and tries to remove those words from every context, as a way to cleanse away ideas they perceive as offensive. That culture and context is quite different than the culture of an open-source git repo that is by common understanding inclusive, global, open, welcoming, and merit-based.
So yes, word master can be used in a slavery context, but that is not our context. As for the maleness notion, I would never have guessed master was offensive because it could evoke a patriarchal, gender, or sexual context, but again that is not our context.
Removing words from our vocabulary does not remove the ideas of those words. The ideas will live on, even if the words do not; other words will arise to replace those deemed unfit by the grievance culture.
My point is that the open source community lives in a different context. The semantic domain of the word master is bigger than those sub-domains that are offensive to some people in some contexts. Evil or oppressive semantics do not apply in this context.
This reminds me of the logical fallacy of illegitimate totality transfer. In this fallacy, one takes all of the possible meanings of a word and imports them into every particular use, without regard to the critical controlling element: the context of the use. Usage determines meaning, and the usage of “master” in this context does not include an oppressive meaning of the term master.
We could discuss whether master should be renamed “main” or “release” or “stable” or whatever, but that discussion should, in my view, be based on the merits of the software-engineering ideas inherent in those words, not the social or cultural meanings of those words–and upon the technical matters of how difficult it is to change such an identifier in the entire toolchain and common usage.