The "PC master race" was a term popularized by Yahtzee from Zero Punctuation. What he did was satirize and make fun of the belief that PC was superior than console in every way. It later caught on because people found it funny, and because, you know, people don't take all that shit so serious. Some people like having fun with that stuff.
So yes, doing the "PC master race" thing is not in any way serious and is just said for fun. You know that? Fun? A thing people used to have before everything was criticized for anything.
I mean, look at this
