I've offered this kind of observation before, but more toward specific facets of P/QF and Christian homeschooling. Since there seems to be a broader range of readers here now, I thought I might offer this in a simple form that applies across the whole spectrum of religious belief.
To Christian parents...
If you have a child (or children) who chooses a different path in life than Christianity (while still living a productive life of decency toward others), and this would in ANY way change your behavior toward or acceptance of this child, then you are a spiritually and emotionally abusive parent, or a spiritually or emotionally abusive parent just waiting for the opportunity to happen. You're also a religious addict with an unhealthy form of "faith".
The same would apply to parents of ALL faiths.
I think it really is that simple, and sadly I think this kind of problem is pervasive even in mainstream evangelical Christianity. It isn't exclusive to the fundamentalist kooks, even if the norm there.
People MUST be more valuable than paradigm.