Its not as absolute as it sounds. While vaccines do have externalities (eg: protection of others via herd immunity), so do the others I mentioned:

Refusing medical care can increase long-term public healthcare costs, especially in countries with socialized medicine, luke Canada

Eating garbage food or drinking excessively leads to chronic disease burdens (obesity, diabetes, liver disease), again impacting public systems and reducing workforce productivity. You could argue that this is mitigate through alcohol tax.

Abortion is more complicated, but opponents would argue there's another life at stake, so from their moral framework, it's not purely personal either.

The "freedom ends at someone else's face" is useful but oversimplified. The real challenge is defining when individual choices cross the line into collective consequences, and which ones merit state intervention. Vaccines are one of the clearest examples, yes, but they're not the only ones with spillover effects.

So my point is how do you define that line, legally? I think it needs to remain pragmatic. Societies change faster than laws do.