Well, for one, they come with a fuckton of nerves that cause orgasms to feel mind blowing, much of which get destroyed by circumcision.
Two, if there’s a flap of skin attached to and covering a body part, and this flap appears on very nearly every single male ever, there’s likely a really good reason evolutionary biology brought it about. Other such examples that come to mind are finger- and toenails, skin, recessed eardrums, the ability to close one’s mouth, and eyelids.
A bit ironic that, in order to prove my humanity, I’m required to select every part of a picture identifying something completely and utterly inhuman. It does, however, serve as an outstanding reminder of what never to be.