No one is shutting down anything, they’re using their speech to classify things as misinformation. You’re allowed to note things are lies or untrue just as much as the people spewing it. There’s a reason regulations and rules exist in the first place, you can’t just lie about ingredients in food for example to protect from harm.

Regardless, misinformation is a real word that applies to things. If you tell someone that says they heard “if I drink bleach it’ll cure my cancer” that is not true and is false information (which can cause harm), there’s nothing wrong with that.