Of course people are free to practice medicine on themselves. They are free to make up their own minds on what they think is right/wrong. They ought not be free, in my opinion, to unduly influence others. At least not necessarily free to spout off whatever ideas they think are correct. Of course this quickly gets into grey areas and situations where the right amount of suppression of ideas gets tricky. It’s OK for government to get involved in this too. For instance we don’t allow peddlers of snake oil to make whatever claims they desire to make. This is a good thing.
I’ll restate my point in a different way. When government is deciding what types of scientific information peddling ought to be banned or regulated it’s best for our leaders to consult the experts of that area.