Do you want to talk about imposing cultural norms on infants that will brand them for life? Okay, let’s talk about language. You only get one milk tongue. What language you speak (and with what accent) not only brands you for life it determines who you can interact with. It is FAR harder to learn a language as an adult, and most people don’t have the capacity to do so really well, even with a lot of effort.
A snipped foreskin, or a tattooed hand is NOTHING compared to the impact of your mother tongue.
And wouldn’t the world be a better place if we all spoke the same language? We could do that in a generation, force every child to learn the same language. Maybe Han Chinese, just based on how many native speakers there already are. And hey, there are plausible arguments that it’s easier to do arithmetic in Chinese, so it may help the brain to learn Chinese rather than something clunkier like English. Yeah, they’d be cut off from their grandparents, maybe even from their parents, but think of how much better the world would be?
Do you support that? Why not? And you are going to get your panties tied in a knot over minor cosmetic surgery?
If you want to argue that male circumcision is a horrible and damaging thing, then sure, make your case. I think it’s damaging enough that I don’t think it should be done without a compelling medical or cultural reason. But yeah, I haven’t seen any argument that it’s so bad it should be reserved for life-saving situations. And yes, I think it’s relevant that the vast majority of men who were circumcised as infants are okay with it having been done.
But if you just want to argue that parents shouldn’t make irreversible decisions for their children, then I think you haven’t thought very hard about what parenting entails, and about just how many irreversible decisions parents routinely make for their children. Most of the big ones don’t involve the child’s body, but even there – whether to vaccinate, what foods you expose your children to, what sort of nutrition you provide, what physical skills you teach them when they are young (skiing? swimming?, piano?) – those all have permanent impacts on the child’s life, and can limit their choices as adults. And the ones that aren’t about the body – what language you teach them, what religious tradition (or lack thereof) you bring them up in, whether they grow up comfortable with dogs, or with strangers, … In general, I think those have more far-reaching consequences than the physical ones. At least, the physical ones that are currently allowed in US society.