No one is honest all the time. We don’t always tell someone that we think their dress is ugly or that they’re a little chubby or that their religious beliefs are ridiculous. Whether or not the avoidance of this kind of honesty is “political correctness”, I don’t know, but I certainly think it takes some level of decency to not voice every thought that comes into your head, even if they reflect your honest feelings.
Some people seem to equate honesty with “rudeness”, which is certainly not the case. But sometimes being honest is rude and disrespectful.
To me, political correctness refers to a kind of language that is deemed respectful. By whomever. Sometimes it’s not necessarily the desired language of the people being referred to (my fat aunt never wanted to be called “overweight”, she preferred “fat”—but I recognize that’s an anomaly).
Look, just be respectful, use some tact, call people what they want to be called, don’t care what someone says is “politically correct” or not. That’s more or less how I live my life and it works pretty well.