That's not entirely a joke. "Halogen-free polyamides are explicitly recommended by the USB-IF in the USB 3.1 specification."[1] Most common plastics do not have a high enough resistance to surface tracking, where, as the connector wears, a conductive path appears across the surface due to dirt and moisture.
[1] https://www.dsm.com/content/dam/dsm/electrical-electronics/e...