It’s their specialty. They pick them because they can control them. They can control them because those that they pick know they could never have attained the positions of power given to them normally, so they’ll ruthlessly say and do anything they have to, to maintain those positions of power. It was a favorite play of the Bolsheviks to keep themselves and their names out of the dirty work. These useful idiots become the targets and not the lever pullers. And they are expendable at any given time.