Forklifts have drum brakes which has a bit to do with it and it's also just how it's set up. Two of the forklifts, at my job,I think you nailed it, forklift pedals are quite a bit farther apart. Curious why left foot on car brakes still seems so much more sensitive though. Maybe just the different used leg/foot muscles.
have a completely different feel than the rest, and also have an auto brake (I hate it, makes you look like an amateur). My other guess would be because it's basically essential to ride the brakes of a forklift, especially if you're in doors and in tight spaces.
It could also just be leverage. Pushing your left foot straight down is easier to apply force than if your foot is more at an angle. I tried driving a forklift with one foot, for kicks, and nearly crashed because of not applying enough brake force with my right foot. Then I panicked as 10k lbs of steel didn't stop when I expected it to. Scawy. It also felt really awkward having my right foot at the angle needed to quickly switch between the two pedals.