Probably several reasons depending on the person.
I've noticed with DA/SA autos that the backlash of the trigger after the sear let off tends, due to the now lack of resistance, for people to dip the barrel downwards.
That and the lack of practice with DA/SA shooting skills leads to those who can shoot well SA, but not well DA.
I think that's the main reason. DA revolver shooters don't have near the problems with that as a DA/SA shooter.
"The government has confiscated all of our rights and is selling them back to us in the form of permits."