I'm also okay banning anti-vax ideas, in defense of the community in general, and in defense in specific of those vulnerable few who can't be immunized and rely on herd immunity.
Foregoing vaccination imposes an as-yet-unaccounted externality on the community; you put everyone at risk by not vaccinating yourself or your kids, and there's no way for the vulnerable (those relying on herd immunity) to know who around them will put them at risk.
It goes way beyond an individual choice, to vaccinate or not. That decision has impacts far beyond the individual's life.
You are OK with banning the idea? It's one thing to make it criminal to endanger your children's health. It's another to put a blanket ban on the speech because you don't like the idea or you think it's "dangerous". The point of free speech is that you don't get individuals deciding who gets to be in charge of what is morally right to say. Society as a whole decides through civil discourse and rigorous debate. But you can't have that if you go around suppressing the other side.
Start banning free speech and you start banning democracy. There is really no two ways about it. This is not a debate about the physical choices people make. Those are either made illegal or not. This is a debate about whether or not people have the right to talk about their ideas. But you are here trying to use a ridiculously nearly undefendable action to spin the argument of some actions are bad or dangerous. Yes they are, but the speech and discussion can only enlighten the public so long as reasonable minds have a chance to speak up against unreasonable ideas. Humanity's resilience comes from the fact that we get to try so many ideas at once out. But if you let a single entity decide what ideas will be allowed you introduce a dangerous weak point into society. The inability to speak your mind only ever brings suffering violence and death. Yes free speech has its problems but it's the best we got.
There is also the problem that someday a company might produce a vaccine that was dangerous to the public, and people that find this out might want to tell others. A strict ban on "anti-vax ideas" would stifle that speech.
Obligatory vaccination is oppression, however you twist it.
How far are you willing to go when it comes to oppressing individuals in the name of the common good? Force women to have children to repopulate aging countries (or, alternatively, force sterilize them in overpopulated countries)?
I don't buy this argument any more than I buy the argument that taxation is theft (it isn't) or that traffic lights are oppression (they aren't).
Vaccination, for those who can be vaccinated (not everyone can), is a trade-off for participating in a society free from disease. Taxation is the price you pay for buying a society and traffic controls are a price you pay for access to a ubiquitous and generally safe road network.
All of coexisting with others is a balance of trade-offs; labeling all of those trade-offs as oppression renders the word meaningless, as much as referring to any kind of coercion as violence.
As for how far am I willing to go? Mandatory vaccines are a good trade-off, and I am willing to stand by the position (one which is growing increasingly popular, as preventable diseases are returning in force).
Forcing women to have children? I have never heard, outside fiction, of a society that forces women to give birth; certainly it's been encouraged, lionized even, but you're proposing something from the realm of fiction as a what-if. Not helpful.
which vaccines? meningitis? anthrax? syphilis? tuberculosis? HPV? hepatitis? flu?
We will never have absolute safety in life. I prefer to have freedom to make the choice because the government will always end up abusing any power we give it.
You're conflating three concepts: forcing people to be vaccinated, banning speech opposing compulsory vaccination, and banning speech arguing that vaccines are a bad idea. In a free society, only the first has any possible justification (based on harm to others if you aren't vaccinated). The second is core political speech. The third is core scientific speech.
Foregoing vaccination imposes an as-yet-unaccounted externality on the community; you put everyone at risk by not vaccinating yourself or your kids, and there's no way for the vulnerable (those relying on herd immunity) to know who around them will put them at risk.
It goes way beyond an individual choice, to vaccinate or not. That decision has impacts far beyond the individual's life.