People shouldn't necessarily be excluded from treatment based on their lifestyle choices ... it becomes a very fine line then in terms of what would be covered ... do we not cover people with high cholesterol or hypertension because they don't exercise enough, overeat, etc?
The bigger issue with anti-vaxxers is that they put other people at risk through their negligence. None of the other groups you mention do that -- with the possible exception of smokers and legislation has already moved towards 'segregating them' from the public when they choose to smoke.
Removing medical treatment for people based on their choices - whether based on addiction, ignorance or 'mental health' - is a slippery slope.
