There's a lot of fighting going on here between Angela and other board members about the merits of vaccination, but I think it's important to recall that someone
did call for mandatory vaccination, and it came from Reason of all places. That is where the outrage is coming from.
Ultimately, I think the Reason author is grossly distorting the definition of force: Force is about making a voluntary choice to use your free will to subjugate others, or to negligently but actively contaminate the environment (other people's property, air, etc.) on a scale that exceeds the "wear and tear" of ordinary living (like dumping chemicals into the water supply, or pumping toxins into the air, etc.). Bacteria and viruses have always infected us and spread through us, and they've been the norm of human life since before history began, so I find it hard to imagine how anyone could conflate someone walking around with an illness (as usual) with pollution on the level of corporations contaminating nearby properties to an unlivable condition.
It is surely possible to spread diseases by "force," i.e. on purpose, like if you get infected by something and deliberately cough in people's faces (or have sex with as many people as possible if you're HIV-positive - just an example of course, so no need for an HIV debate here

). However, most of the time, diseases spread by complete accident. Sometimes, that's just life. We call it force when you shove someone, but we do not call it force when you trip and fall into them. A victim may be entitled to restitution nevertheless (if you accidentally knocked them into a table and gave them a concussion or something), but how would it be libertarian to
preemptively force the purchase of extra-balance-preserving shoes from e.g. New Balance (not that I dislike New Balance) as a preventative measure? That is after all the very kind of thing this author is suggesting, except in the case of New Balance it's a lot less invasive.

If you take this "preventative" logic to its natural conclusion, you can justify literally ANY amount of force in the name of "keeping people safe," up to and including enacting laws that ban you from leaving your house (because you might track water onto the convenience store floor, which an old lady will slip on and die from).
It seems to me that the mandatory vaccination crowd is not a fan of either individual liberty or even democracy but pure institutional authoritarianism. After all, a small handful of refuseniks is never going to be enough to seriously damage "herd immunity." The only way "herd immunity" could ever be damaged is if a LARGE percentage of people chose not to take vaccines. If that ever happened, the forced vaccination crowd would say something like,
"So what if so many people disagree with me? No matter how many there are, even if it became a majority, their opinions about what to do with their bodies don't matter. Only OUR opinions about what to do with their bodies matter, because we side with Science (TM)...and don't give me that tripe about science being about the scientific method. Science is about faith in the authority of the most prolifically journal-published scientists!" So...by that logic, why don't we let appointed institutional leaders in ALL areas make autocratic decisions for everyone about what's best for them? It worked well in the good old USSR!
For the record, I'm mostly vaccinated. I believe in the utility of vaccines, but the benefits of probabilistic immunization have to be weighed against the potential risks, and that's a personal decision. In many cases, the benefits outweigh the risk to me. In others, they don't. I can't weigh in on the autism debate, but I do know that people have occasionally died from vaccines. That's a fact I have never seen contested, and I think it lays bare the obvious: Forced vaccines are about stripping people's free will to make their own risk/reward judgments, supplanting it with your own, and violating their ownership of their body to stab them with a needle, for your own presumed benefit. You can sugar-coat it all you like, but at the end of the day it is not libertarian in the least.
Even aside from the issue of personal liberty, the coercive vaccination crowd seems to forget: Putting all of your eggs in one basket and creating a monoculture is rarely a good idea. Nature is VICIOUS when it comes to annihilating monocultures in one fell swoop. Here's some science for you: Monocultures are how extinction happens. If something ever goes *really* wrong with a particular vaccine, you don't want it to be the vaccine everyone was forced to take under pain of rape cage. "Whoops, we didn't know this mass-manufactured vaccine was contaminated with extra DNA bits that would accidentally sterilize everyone. Here's your $2 settlement stake after the class action lawyers' cuts. Enjoy watching humanity's extinction."