I never said PC, I said social pressure. Just like social pressure against drunk driving. The high rate of deaths due to drunk driving used to be something that people just tolerated. People joked about drunk driving. With a combination of stiffer penalties and MADD outreach to media groups that educate the public, people no longer just accept that a drunk driver "made a mistake" and placed social pressure on people to stop. This also made it acceptable to talk to friends who were about to drive drunk and get them to take an alternative. That's social pressure. Nobody calls it PC to try to talk somebody out of drive away drunk or to tell them later that they should not have done so.
PC is just right wing's way of denigrating others who find gratuitous insulting others unacceptable. Social pressure puts the racist on the back foot by letting them know they will no longer be welcome in a social group if they continue to behave like an ass. Just like drunk drivers are no longer laughed at or given a pass when they drive drunk. Over time, social pressure is much more effective at changing behavior than laws. Laws are only one part of the means to change attitude.
Racists of course hate this.