When you have posters who can dismiss everything said here as a "snide attempt to call Jews and Muslims child abusers" and others trying to argue that it's essential for THEM and THEIR religion to have the child cut, or who dismiss references to actual frequent practices in some countries as "islamophobia" rather than acknowledging it happens and being glad it doesn't happen here - well, you're just not dealing with a rational thought process. You're dealing with people trying to defend what their family has done/what they've done.
Of course it's important to the religion. My goodness, if you didn't indoctrinate people from a very young age, however would you keep it going? The whole point is not to let them have a free choice (As to which see the huge decline in Christians attending church in the U.K., precisely because our society has moved on [and also because we have welcomed a lot of other religions and cultures] which have increased the population). So all those parents patting themselves on the back for doing a great religious thing are just buying into the same old pattern.
For some people it can also mean becoming quite closed off from other communities - to give just a tiny example, I once worked with a lovely Jewish girl, whose second sentence to everyone was, "and I'm Jewish." She wouldn't go out and socialise with everyone else, because she always had to do stuff with her family, and she had never dated/wanted to date anyone who wasn't Jewish (then she wondered why it was hard to find a boyfriend when she'd made the pool so much smaller!!). i just can't understand saying, "oh I could never date a black man/Asian chap/Muslim dude/atheist". To me, you take everyone as you find them, and then you decide if you like them. But to her, it was an immediate split: Jewish or not, and people were then treated accordingly - friend/boyfriend or acquaintance. I had another colleague who was a devout Christian. She'd never dated anyone because she was committed to no pre-marital sex, and she left work early every thu and fri to teach that to the teenage youth group at her church (wonder how that worked out!!). She also wouldn't come out and socialise with work or clients at all, preferring to rush off to her church and her family.
Of course not everyone is like that. But that's how some people are, because religions like to keep you close once they've got you!