As sure as prehistoric fish grew legs and sauntered off the beaches into forests working up some irregular verbs for their first conversation, so three-year-old children enter the phase of name-calling.
Every day a new one arrives and is added to the repertoire. You Dumb Goopyhead, You Big Sewerface, You Poop-on-the-Floor (a kind of Navaho ring to that one) they yell from knee level, their little mugs flushed with challenge. Nothing Samuel Johnson would bother tossing out in a pub, but then the toddlers are not trying to devastate some fatuous Enlightenment hack.
They are just tormenting their fellow squirts or going after the attention of the giants way up there with their cocktails and bad breath talking baritone nonsense to other giants, waiting to call them names after thanking them for the lovely party and hearing the door close.
The mature save their hothead invective for things: an errant hammer, tire chains, or receding trains missed by seconds, though they know in their adult hearts, even as they threaten to banish Timmy to bed for his appalling behavior, that their bosses are Big Fatty Stupids, their wives are Dopey Dopeheads and that they themselves are Mr. Sillypants.