But stopping the use of the master-slave metaphor in tech has nothing to do with assuming there are "hyper-sensitive, fragile babies who cannot understand nuance of speech" it has to do with real metaphors that persist in tech, which hold problematic historical baggage.
The IETF has a document with the clearest and most informative statement on this that I know about: https://tools.ietf.org/id/draft-knodel-terminology-00.html
Besides, "trunk" is an objectively more correct metaphor for the main "branch" in a "source tree".