1) They are godless in their worldview. The children who attend will learn to think godlessly. They must just to cooperate in the godless classroom. How could it be otherwise?
2) They risk learning to be comfortable with socialism. Government schools are the very definition of a socialist-funded, single-payer, and compulsory use entitlement. They risk learning that a voting mob that is powerful enough to give them tuition-free schooling is powerful enough to give them lots of “free stuff, force them to pay for it, and force them to use it.
3) All government schools suppress every First Amendment Right.( speech, press, assembly, free exercise of religion, and all government schools teach the religion of atheism). All schools must just to maintain safety and order and all schools have a non-neutral religious worldview. However....When government does this the child risks learning to be comfortable with the government suppressing his God-given rights.
4) Government schools are compulsory for all children whose parents can't afford the jizya to ransom their child by way of home or private schooling. Children attending government schools risk learning to be comfortable with government compulsion.
Just so I am clear you are admitting to child abuse when you willing sent your children to public school. That is what you just said.