Arguing in bad faith, and exploiting logical technicalities exist, and are widely used to sway the opinion of the masses. this is something any rational society needs to take into account in my opinion.

Both of those are cases where people tried to suppress movements and legitimate problems via authority.

So to me, your comment comes across as “But what about those cases where what GP said is true?”

I don't think almost anyone has faced consequences for being anti-vaccine. That's been extremely free-speech, and it hasn't helped people come to the right conclusions at all.

That’s just not true — consequences for not having their children vaccinated are legislated lots of places; the arguments against anti-vaxers are often appeals to the same authorities that happily over-prescribed opiates and based around shaming them; etc.

I'm talking about what people say, not what they do with their children.

But can you be more specific? What consequences can you name, especially in the US? I'm not aware of there being almost anything in the US, except that they might not be allowed into some schools, which barely even counts as a punishment.

And yet the idea proliferates wildly.

"Michigan parents are legally allowed to skip or delay their children's vaccinations due to personal beliefs.

But Bredow fell foul of the law because she reneged on agreements with her former spouse dating back to November 2016 to have the boy immunised."

Sounds like an edge case that's more about custody than legal rules over vaccination.

I do hope you realize that people being anti-vaccine can and does result in the deaths of completely innocent parties.

The consequences for people not vaccinating their kids goes beyond just belief. Even then in America we're incredibly lax on those people despite the fact that it seems to be growing movement fueled by quackery.