Well OP, I don't think arguments from evolution will get you very far, but roughly it look like this.
The foreskin evolved to be the way it is. We don't know why, but it must have been something that gave a marginal advantage in surviving to have children. Probably not a female preference thing like the peacock's tail, more likely purely protective. If you're running naked around a forest it's probably a good idea to have the rather sensitive glans protected from being stung by a wasp or sucked on by leeches.
Ok, you can uncross your legs now.
That reason no longer applies in modern societies because pants exist. Well, mostly. You might prefer to have been uncircumcised if you ever catch your dick in a zipper.
(I lied about the uncrossing your legs part.)
None of this is relevant to the modern practice of infant circumcision, a practice which I oppose on the grounds that if you did it to a non-consenting adult you would get banged up in jail for wounding with intent, so why the hell should it be OK to do it to an infant?