They think they learnt a lesson once. That may have been they got outsmarted by someone or bullied. Something caused them pain they could not deal with. The coping mechanism is to go out into the world and prove themselves smart and "more than" by cheating "idiots" who by definition must be "less than"

They're just hurt egos. Feel sorry for them. 

 Absolutely, it's important to remember that hurt egos often lead to negative behaviors. It's always good to approach these situations with empathy and understanding. Feel sorry for them, indeed.