The problem is that, specially looking at religion, it's better at oppressing free speech than free speech is combating the fallacies that lie at its heart. It's purpose build for that.

Now I'm not saying you should outright ban religion and be done with it. You should try to out argue something first, and if you get in serious trouble you might consider a form of censorship. They're not mutually exclusive. What censorship gives you, that arguing doesn't, is a tool to fight something that otherwise would have nasty consequences.

It's like taking care of your health. You try to live a healthy lifestyle, exercise and get your shots. But if you become ill anyway you take pills to get better. Arguing is a healthy lifestyle, but you might get ill anyway. You'll need to something when you do, and that might be to censor something.