If by cosmetic circumcision you mean the circumcision performed by numerous doctors unto newborns across the USA, then yes, I am absolutely against it. It is a horrible practice to perform to a baby, when you're essentially cutting the top of their dick off without a shred of any medical evidence supporting it, all because of some kind of weirdly disturbing stigma of American society.
Religion, fine, because as far as I know, they don't do it to boys when they're babies, the only religion I know that does this is Judaism and they do it when the boy's about to become a man, fine. That's at least 2000 years of a weird-ass tradition I'm not even going to touch.
But this is about cutting skin from a newborn's penis. It is sick, it is wrong, it is nothing but sadistic abuse to a newborn that causes dangerously high pain and stress levels in them just after birth, and all because of Mr John Harvey Kellogg the cereal magnate, who was a twisted fucker thinking how boys shouldn't be masturbating or touching their dicks at all and basically just cut their dicks wantonly without anaesthetic.
There's nothing supporting anything beneficial from circumcision, just as there's nothing supporting anything beneficial against it, it's a completely pointless thing to do, nothing good or bad comes out of being circumcised, so why even bother causing so much pain to your newborn just because his dick looks A LITTLE BIT MORE PRESENTABLE?
If he wants to be stupid enough to cut his own dick, he can damn well do it as an adult himself, it should NEVER be the decision of the parents, and I don't know what kind of parent would willingly allow someone with a scalpel anywhere near their baby's cock, but I can't blame them for being ignorant.
Besides, no medical authority in the world recommends it as a course of action, mainly because it's just pointless, all it does is cause pain and waste money. Fuck you Kellogg. Fuck you and your sadistic abuse of the laws of healthcare.