The word “Master Race” is clearly equivalent to terms which were used by Nazis and so are today’s far right wing and alt-rights.
There are other communities which created similar narratives, especially from the 4chan side, and I think the origin of “PC Master Race” comes from there.
The origin of the phrase “PC/Linux/whatever-non-serious-thing master race” is self-deprecating. It’s an ironic jab at the enthusiasts in these communities that take themsevles way too seriously and gatekeep users of other platforms.
Do you know of any actual minorities who are upset by this phrasing, or are you just white knighting?