An onov would judge the child and the parents by their middos and by the home they keep, and hope to find kind, gentle, honest and trustworthy people for their kids to interact with.
Any parent has the right and responsibility to choose who their children interact with, at least at young ages. It’s the criteria you use that will illustrate YOUR character, the assumptions you make about others that will reveal your gaivah or anivus, the decisions you make that will impact your kids capacity to practice ahavas chinom.
Choose wisely. It’s not just your life and prejudices you are playing with. It’ll affect your children’s capacity to learn how to judge for themselves, which they will eventually need to do.