Master as in “master’s degree” is from a Latin word meaning teacher, and it’s the same root for mastery. I think most of the concern about tech usage comes from introducing the term “slave”, either directly in a pair or, as with Git, deriving from that usage. It’s that specific pairing along with the technical inaccuracy which makes master/slave considerably more likely to offend, in my opinion. If someone came to me and said, however, that they didn’t like the term and wanted to change it I wouldn’t object because it costs me so very little to be respectful of the fact that not everyone comes from the same place.

Blackbody radiation, black hole, etc. similarly doesn’t have the same pairing as you get with white/black-list - it’s a physical phenomena, not a problem. The concern isn’t using the word black but using it in a context which reminds the reader of racist use of the same words in other contexts.