I’d like to see parents of unvaccinated children criminally charged with child endangerment, if not actual attempted murder.

I think you may be confusing "satisfying" with "sane".

Unfortunately, the sane response is to try to help even the incredibly dumb people from the consequences of their actions, if only to limit the impact on the rest of society. If treatment isn't covered, then they won't seek treatment, their disease will get worse, and it will spread further.

they promote vaccination and preventative care and its free to avoid paying for infectious diseases which can cost them alot of money, antibiotics, antivirals, hospitlizations, surgeries for unvaccinated people. thats why they charge Hospital visits quite a lot to discourage people form using it.

wether they will deny care is probably going to be tricky depending on the insurance, and even your region.

It's one of the most horrible ways to die and these people are enthusiastically inviting it on their kids.