Much of what people know about libertarians comes from its opponents. Actual libertarians believe that the proper role of government is to protect peoples rights, while maximizing their freedom. Proper regulations would be aimed at preventing one group of people from hurting others.
"For their own good" regulations, though, are not libertarian. Adults should be allowed the freedom to make their own choices about themselves.
P.S. I got fully vaccinated at the earliest opportunity.
Were they libertarians? Well, I can't say for certain, but I think that seriously trying to argue they weren't gets well into No True Scotsman territory.
Regardless, almost every self-proclaimed libertarian I have ever come across has absolutely argued against government regulations, with the possible exception of those supporting property rights.
There are various types (or degrees or flavors or something) of libertarianism. Minarchy [0] is one type, but doesn't seem to be the most vocal from what I've seen. There's even libertarian socialism [1]. The most vocal type seems to be anarcho capitalism [2] which is pretty much the no government whatsover group.
[0] https://en.wikipedia.org/wiki/Night-watchman_state
As will adherents to every political persuasion. Some even go so far as to violently purge their impure members.
You may not think they are credible, or libertarians, but I'll ask you not to deny my lived experience just to support your personal idea of what a libertarian is or should be.
The libertarian argument that you're almost certainly mischaracterizing there is about the pandora's box that is opened by allowing the government to decide what is or is not "poison" (which is of course an absurdly emotionally charged word picked by their opponents). Consider that some governments want to restrict sugary food on health grounds. Sugar isn't a poison but once you accept the principle that governments can ban companies from selling "poisoned" food, the definition of poison immediately comes under attack and sooner or later means almost nothing like what you'd expect.
There are always going to be grey areas, such as the line between "safe" and "unsafe", and Libertarianism doesn't provide any guidance on where that line should be. The government's role is to define that line, and the courts to interpret it as part of checks and balances.
Michigan politicians that like to label themselves as libertarian supported socializing the cost of vehicle accidents. Of course repealing an insurance mandate is pro 'personal freedom' on the surface, but in context of reality, all it does is transfer costs from a user fee to Medicaid, which is not libertarian at all.
As much as freedom of speech and decentralization is important, constant attacks on this and that in isolation lead to the incorrect conclusion that everything must be thrown away. It’s a product of no one person, but many contribute to the entire macro problem, which means no one also will accept responsibility for the entire mess that were now in such that half the country doesn’t want to save their own and others lives despite a dangerous pandemic by using a safe and paid for vaccine alternative.