"Master of <subject_matter>" is pretty clear in that a person has mastered a trade or an area of study! No one confuses that with the idea of "Master/Slave" or "Master Branch" which implies a hierarchy that reminds some people of slavery, particularly the slavery that was practiced in the US.
There's an obvious contextual difference, and it's not some political conspiracy from an imagined "leftist elites" that I assume you think are coming for you. Conspiracy theories are unhealthy and I personally think you should let this one go.