I've always somewhat mixed feelings about PC. Yes, I get that it's a way to encourage greater respect and courtesy, although I often found it coming up in discussions I would see about movies which came out before the mid-1980s.
The 70s were also pretty raw in that there really was no "PC" to speak of, although one could say it was still comparatively better than it had been in previous decades. An example might be a TV show like "All in the Family," which was considered rather progressive and liberal in its overall scope. But by the time it was in syndication and being rerun in the 90s and later, it had to carry a disclaimer and warning for some of the subject matter and language.
I've also noticed it in some of the more recent reviews of early 80s movies like "Sixteen Candles," which is attacked for a number of reasons which probably few people even thought of back when the movie came out. "Revenge of the Nerds" is another one like that. Still, the realm of comedy and humor has been given some latitude when it comes to pushing the boundaries of PC.
One thing that I remember rather well in the early years of "PC" is when Jimmy the Greek got fired by CBS.
His remarks may have been the result of drunken buffoonery rooted in ignorance, but he didn't seem to come off as deliberately malicious or hateful. So the question may be asked: Does the PC "punishment" fit the "crime"?
It reminds me of my grandfather and many of his generation who grew up in a completely different time, yet still did not bear any open malice or ill-will towards black people. But they still grew up in a segregated society and were raised with a lot of strange ideas. In his own clumsy way, my grandfather would try to be "nice" but end up putting his foot in his mouth anyway. But he wasn't hateful or mean, nor did he really intend any disrespect.
That's where PC might tend to lose a bit of perspective, since it doesn't make any real distinction between that which is intentionally harmful and malicious versus that which may not be intended to be harmful.