It's a little hard to believe that people who famously don't use computers were infected by an "misinformation", a rather loathsome neologism. There was famously a really serious outbreak in the NYC Orthodox community from 1989 to about 1991. Unvaccinated communities are a sort of immunological tinder box, and you never know when a stray spark might land.
This is the result of a failure of public health to reach out to these religious communities in effective ways for decades.
That stray spark’s survival is heavily influenced by the herd immunity of the rest of the population.
Put another way if the overall population sees an average of 0.5 or 0.95 infections per case there’s zero chance of a huge outbreak. But odds of a case making it to a vulnerable population is wildly higher in the second case.
I'm not sure about Mennonites. One of their communities writes about it and seems to suggest only 1 of the 40 or so communities is hardliners against vaccination. But I also note this is written in a really neutral way (could be to placate government, dunno): https://www.mennoniteusa.org/measles/
This is the result of a failure of public health to reach out to these religious communities in effective ways for decades.