On the other hand, for the non/new developers I’ve interacted with [non-US], “master” was a confusingly jargonistic name that has raised eyebrows for years. Being the “main” branch seems a much plainer, obvious name, and I think it’s an improvement entirely separate from any social reasons.

Is it an empty gesture? Maybe? Does it cost more than a couple of seconds for making things clearer and making a minority of people people happy? No.

It probably wasted more integrated time across all the people reading this article than just shrugging and changing it does.