Must be because they insist on using their left foot for the break while keeping their right foot still on the gas.
The left foot is for the clutch period!
You want to slow down or stop, take the right foot off the gas and apply the right foot to the break
I’m a two-footed driver. Learned to drive racing go karts, then graduated to sports cars. I don’t ride the pedals either. Because of my experience, my reactions are very fast, there’s no dead time in between shifting from gas to brakes. But I don’t think I’d recommend this method for all drivers.
Ask 100 women what a “clutch” is, and 98 will say it’s a handbag.