Except that those who complain about having to be "politically correct", generally imply they shouldn't be beholden to general respect for people's choices, race or circumstances. "Political correctness" is societal shame (one of the best motivators around, according to behavioural psychologists), and people get defensive out of guilt.
The issue you equate people against political correctness who mostly belong to the far right and people who complain about the excesses of political correctness which is far more mainstream to be the same, which is unfair imo.
General politeness = general politeness.
Political correctness is more about a societal debate about to which extreme do we have to shape our expressions or actions towards others.
Political correctness is defined differently as the avoidance,
often considered as taken to extremes, of forms of expression or action that are perceived to exclude, marginalize, or insult groups of people who are socially disadvantaged or discriminated against.
It is more the excesses of political correctness that frankly hurt progressive causes as it undermines them with silly wedge issues and become diversions from the actual 'injustice' and gives fuel to opponents of progressive ideals.
Therefore not everyone who has issues with political correctness is a racist or etc, they frankly find people that are 'too Politically correct' undermine the causes they believe in as they become a distraction from the bigger picture.
For example, Justin Trudeau feminist agenda was well received but to have an entire budget called a feminist budget and then saying stuff like 'peoplekind' was so politically correct that it started to undermine the feminist agenda put forward by the PM and why you have seen the PM move on from such rhetoric.
So the issue is the excesses of political correctness, not political correctness and many of my liberal friend in university roll their eyes when people get "too pc" and many comedians, TV shows commentators who would be considered left leanings have ridiculed PC culture when it gets a bit absurd.
So I think that nullifies that everyone who says you are 'too PC' is some old white conservative guy lol.
Of course, Ford and Trumps rally against political correctness are dog whistle politics.