So imagine you're playing a game with your friends, but there are some rules about what you can or can't say. Like, you can't say anything mean or hurtful to someone else, or you can't say things that might be offensive to others. This is kind of like what "political correctness" is about.
Some people don't like those rules, and they want to be able to say whatever they want, whenever they want, without worrying about hurting someone's feelings or being offensive. They think that being politically correct is restricting their freedom of speech.
But other people think that those rules are important because they help us all get along better and treat each other with respect. They think that being politically correct is just a way to be polite and considerate.
So basically, there's a debate going on about whether or not we should follow these rules about what we can or can't say. The campaign against political correctness is a group of people who think that we should ignore those rules and say whatever we want, and they're trying to convince others to do the same.