European here. I'm a supporter of civil rights and against racism and so on, but that controversy with master vs main for me is just a silly us american controversy, as master has more meanings that just owner of a slave (and in this context, it's not even related to that master-slave thing as used to be in hardware naming).

The issue is that kind of (in my pov, unnecessary) change caused an outage in my company as some k8s objects changed its label because of this kind of controversy, and some of our selectors were not ready for that change, as iirc this happened in a minor version upgrade. We also had to invest development hours to update internal tooling to support that change too (and I bet, a lot of companies did the same).