As far as I've met people, there are three groups:
- Those who believe that anyone who doesn't vaccinate "isn't intellectually capable of making good medical decisions"
- Those who are opposed to vaccination because they believe in conspiracy theories
- Those who are are either pro- or anti- vaccination, but realize it's a complicated issue, with evidence-supported pros and cons, that other humans of reasonable intelligence can have different opinions than themselves about
Unfortunately, the first two groups tend to be the loudest and most religious about it.