Why Are You Trying to Fluff My Non-Existent Fur?The obsolete reflex that turns us into plucked poultry

From the show

Oh, god... really?

Piloerection forces tiny muscles to raise hair follicles, a mechanic designed to trap heat or intimidate predators in furry animals. Since humans lost their thick coats millennia ago, this feature merely turns skin into a bumpy, useless landscape. We demand to know why this vestigial trigger wasn't removed when the fur was uninstalled.