I do and don't agree with you, Hope. Any kind of extremism is damaging to a child - political, animal rights, even having the kind of parents that obsess over image and stuff. But Fooo is within her rights to ask about the damage specifically caused by the 'your loved ones will burn in Hell' extremism associated with some kinds of Christianity.
That's right - the issue here isn't merely about religion, let alone simply christianity. The point is that parents have an exception level of power over their children in terms of potential indoctrination, and parents need to recognise their responsibilities that go along with that power.
To my mind, as a parent, it is essential to understand that your children aren't simply 'mini-mes', impressionable minds to be shaped to think exactly as you do. No, they are people in their own right and the key responsibility as a parent is to create an environment that allows those young people to become themselves, whether or not that is similar to their parents.
At our welcoming ceremony for our own children we had a reading from Kalil Gibran, which put this point in a much more eloquent way than I could:
'Your children are not your children.
They are the sons and daughters of Life's longing for itself.
They come through you but not from you,
And though they are with you yet they belong not to you.
You may give them your love but not your thoughts,
For they have their own thoughts.
You may house their bodies but not their souls,
For their souls dwell in the house of tomorrow,
which you cannot visit, not even in your dreams.
You may strive to be like them,
but seek not to make them like you.
For life goes not backward nor tarries with yesterday.'
There is an equally fantastic piece on marriage which we had at our wedding.