Jen SorensenLatest comic on the ever-expanding meaning of the insult "PC"
Rachel Rawlings@jensorensen Having been left-adjacent before the 90s, back then we used it to describe someone who thought eating a pulled pork sandwich was the same as giving aid to Newt Gingrich. Then Poppy Bush used it in a 1991 speech and Bill Maher got his talk show, and it metastasized into a right wing cudgel.
Adrian Riskin 
Came here to say exactly this. As early as the late 70s (in my personal experience--maybe earlier) PC was an exclusively lefty term for bossy and extreme wannabe political commissar types and then all of a sudden the YAF types took it up and the story told in the comic strip began.