Insults

This is not exactly a deep thought, but I wonder why classic insults typically include body parts that are usually contained in a set of jockey shorts:

"Hey! DICK FACE!"

"Did you hear what she said to me? What a cunt."

"No. I said Combo #1, penis-breath."

And of course, there are the combinations:

"Suck my dick, you retarded asshole."

Who decided these are the insults? Society has taught us that these are the bad words, but what if back in the day, our ancestors had arbitrarily chosen different body parts?

"I say, give me my shield, you dimwitted kneecap."

"That's right. Lick my elbow, you wench."

"Where is my mead, you useless earlobe?!"

But it's probably not arbitrary at all, but because disgusting bodily emissions usually seep from the insulting orifices we are familiar with.

That is all.