However, in the BIONICLE universe their entire personalities are based off of faulty programming and glitches. They were meant to be nothing more then mindless drones untill Velika screwed it up. however in Hero Factory, they are made to have personalities, minds, and the ability to make choices. Quaza cores help give them a better understanding of what is right and wrong.
Indeed, and that past Hero is the serial killer known as Core Hunter. Von Nebula was speculated to have been faulty, but the Hero Factory never was able to do a proper diagnostic. He still made those choices though, even if his programming was faulty, is it much different from some human being evil?