A vaccine that only conveys, say, 20% protection to individuals can still convey ~100% protection to a group by tipping disease story from "spreads exponentially" (average_new_infects_per_person > 1.0) to "fizzles out" (average_new_infects_per_person < 1.0). That's called herd immunity. Even a modest minority of anti-vaxxers can sabotage herd immunity, leaving the rest of us with only the vaccine's individual protection margin.
Which just brings us back to worrying about the concerns of others.
What does herd immunity have to do with the lives of the vaccinated?
An increasingly large population of infected risks giving the virus a foothold first in vulnerable populations, then in everyone especially as mutations in an increasingly large reservoir provide exponentially more chances to find more effective forms that bypass existing immunity.
A minority of stupid people can put everyone at risk. Ultimately diseases continue to wipe out species. There is no particular reason to suppose we are immune to calamity just because we have better tools to respond to it than dumb animals.
If some minority of children aren't vaccinated, how is that a threat to the rest who are? What's the point of the vaccinations if they aren't effective at protecting the vaccinated from the diseases carried by those who aren't?
I must be missing something, because it just looks like people meddling in the affairs of others. If a parent wants to have non-vaccinated children, I don't see how it's any different than a parent letting their children grow obese. It's their problem, live and let live.