Your equating of PC speech restrictions and Christian efforts to have movie labeling is not at all fair. Christians wanted to protect *their own children* against certain influences in a culture that suddenly and without their consent changed into something completely different than what they had grown up in. They weren’t trying to stop you from seeing what you wanted or show your kids what you wanted.
Forces inimical to Christianity took over mass media and started exposing Christians to things they did not want to be exposed to and attempting (often successfully) to indoctrinate their children. There is a big difference between objecting to having your kids exposed without warning to sex scenes and getting someone fired for making a crude joke about “nappy-headed hoes”.
I’ll admit there was another aspect of Christian attempts to restrict culture, and that was their attempts to stop things that they found deeply offensive and sacrilegious. However, in this they were only asking for the courtesies that are extended to everyone else by PC. No one in the larger PC-controlled media deliberately offend Muslims, Jews, Hindus, Native Americans, Blacks, or any other group that is PC approved. To the extent that Christians tried to stop movies and art projects that were deliberately offensive to them, they were just asking for equal treatment, not special protections.
Neither of these things is equivalent to what that the modern speech police does.