"why is it that public school teachers put their children in parochial schools?"
For most public school teachers the traditional Catholic Faith isn't a priority.
For those blessed to have the right priorities in life, the marked modernist disorientation of parochial schools doesn't present much of an advantage.
Why not teach children what's most important for their eternal souls rather than leaving them to the perverse modernists who prowl about parochial schools like hungry lions seeking souls to devour?
In the wake of Vatican 2, it's been found that less than 5% of children "educated" at "Catholic" schools keep the Faith after leaving school.
Good point. I know some who've done this.