Leaving aside the humor of saying "for chrissake" when talking about Jewish tradition, the Jews didn't take up circumcising babies because they thought it would be fun. You say you're sure God won't mind if they wait, but according to scripture that isn't what God said. According to scripture, as I recall, it was to be done to male infants eight days old, and any male member of Jewish society to whom it was not done would be cast out as one who had violated covenant with God. So maybe God does mind. I don't know.
I saw it, and left it because it amused me.
The point that Lilias brings up is good, too: There are different kinds of circumcisions, and the one most widely practiced now snips away a good deal more than is needed for someone to be considered circumcised. And saying, oh, it's only a difference in sensation - that's like cutting off the labia minora and then saying, "Well, it's only a difference in sensation". There are plenty of medical and ethical reasons not to perform a circumcision on a newborn, and the majority of parents don't even have religious reasons to stand on. "Well, it's my child and my choice!" someone might cry, but the truth of the matter is, a parent has no right and no business cutting their child's genitals unless there is a medical reason to do so. But, if someone were to insist on the right of a religion to mutilate its children's genitals even though the child may not even follow that faith later, they should at least shoot for minimal damage and not the current lop-the-whole-thing-off movement.
There are some traditions that are held over from the Old Testament that don't harm others, and that I understand. Kosher laws, fine. Cutting into other peoples' bodies, not fine. I think that if you believe in God and you believe that He created us, then it's a little silly to think that He created us with something He doesn't want us to have. If He didn't want little boys to have foreskins, He wouldn't have created the foreskin. It seems so simple to me;
it's a law that comes from a book that allows for selling your daughter into slavery and stoning people to death.
: Actually, I can't remember if it's Leviticus, the Bible, or some other holy script that instructs Jewish men to mutilate their genitals, so I'll strike that part out in case I'm misremembering.) And in my opinion, it's barbaric.
That said, I should probably note that I'm not really sure that the law has a place in this. The purpose of the law is to protect those who cannot protect themselves, though, including from their own parents, but it's an awfully intimate thing to be legislating. So I don't know.