See, I figure...
And this is totally IMHO...
...if I guy is really bothered by being uncut, and decides as a teen or adult that he wants to be circumcised, he can do that. It's not pleasant, but it's his choice. If my son decides at 8 or 10 or 16 that he wants a circumcision, I'll support him and I'll pay for it.
But if a guy gets cut as an infant and decides in later life that he'd rather have been left intact...
...there's no getting off the circumcision train, at that point.
I'm totally fine with people who circumcise their infants, I should point out, even if they do not have religious reasons to do so. And having only ever had circumcised lovers, I do have an aesthetic preference for cut cock. But I figure, I don't care what my kid's wang looks like as long as it works right. And the American Medical Association has agreed that there's no functional benefit to the procedure. So why bother?
For the record, I feel similarly about infant baptism -- I think Christians should be baptized when they feel ready and can understand the significance of the ritual. My kids are unbaptized because I feel odd making a promise on their behalf. So the circumcision thing is part of a larger value set surrounding which choices we have a right to make on behalf of our children, and which ones are best postponed until they can choose for themselves.