Left hand lug nuts are back, baby!

In NASCAR Cup, all 4 corners of the car have (single) left-hand threads on the hubs/nuts. There are 6 drive pins on the hub, and 18 drive pin holes in the wheels. The wheel can't spin, or come loose, if the pins are engaged and the nut is tight. But nobody seems to know why they are using left-hand threads on all 4 corners.