Why is that any of your concern?
Because of something called 'herd immunity', a well-vaccinated population is unlikely to be infected with the diseases vaccinated against. Once the unvaccinated group reaches a 'critical mass', then even vaccinated children can get the disease (though usually in a milder form).
A small number of kids can get a free ride because all the others are vaccinated, but when you get up into several thousand unvaccinated kids, the risks increase substantially.
My kids didn't go to public school, but they wouldn't let my kids even register for their private school without a certificate of vaccination.
I'm old enough to remember the days before MMR -- and the kids who were blinded or retarded or killed by measles or rendered sterile by mumps. I'm not quite old enough to remember when they closed the swimming pools because of polio epidemics . . . but EVERYBODY got their kids the polio vaccine because they remembered those days. The dad of a good friend of mine was paralyzed at age 16 by polio.
Hmmmmmmmmmmmmm I merely ask...Why were these children allowed to start school? because my children and grandchildren have all needed their shots up-to-date and proven to go to school...
And you slap me down with an unwarranted “Why is that any of your concern?”
is there more to this story? What are you hiding? Are these illegal alien children?