I think there is no final arbiter between good and bad, and change (for better of worse) starts at the fringes of society, the law, morality, political correctness. IMHO it is indeed unwise to go full thought police, but it is equally unwise to assign anything 100% true or false. Even Richard Dawkins is not 100% claiming there is no God (6.5/7 he calls it, don't ask someone to prove a negative). We all hold believes that are false. Some very obviously so to others.
So perhaps a Christian could convince me, perhaps even a flat earther. It’s just extremely unlikely and they’d better hit me with a good argument in their first sentence because I heard and dismissed many many arguments before.
But you are right, false believes are not harmless, see [0]. But, much like we can either have good encryption OR backdoors, you either have freedom OR you don’t, nothing may be “in between”, criminals using Signal and people thinking wrong stuff is just something that needs to be dealt with differently. (Because we want private communications and we want freedom.)
But I’m about 10% convinced I’ll have changed my mind on this in 5 years.
[0]: http://whatstheharm.net/