PC = Politically Correct. The term and acronym have 2 or 3 decades of usage. MM's efforts to redefine it aren't likely to succeed among DU-folk, who spent those decades denying the phenomenon exists.
The simpler word for MM's phrase is, "Polite". That's something DU-grade Libs & Progs have derided and eschewed since the 60s. They aren't likely to change their ways 4-5 decades later.