They actually don't care if the kids are religious. They just need them to be uneducated, pliable, and poor. Then when the religious mood shifts, the owners can just move public opinion wherever they want it.
This isn't about ideology: It's about money. They want the tax dollars in the private schools because they own those schools. They don't want the Catholic Church or the UMC getting their hands on that money. They want it going into standardized tests and "accredited" curricula--nice, private, for-profit industries the owners can use to fatten their portfolios.
It's funny b/c the whole point of school (except that's absolutely not it, but you know... since when have "facts" mattered to those type?:-P) is to indoctrinate kids into behaving appropriately in a corporate environment.
But that's not enough, and now they want to indoctrinate them more. Shocker: the vast majority of those kids want to leave those areas and never come back, if they can only scrape together enough money to make it happen and find a job elsewhere (despite lacking any skills).