Nothing hurts a bully more than being ignored
Absolutely this. I've found it fascinating to watch the different behaviours that a bully goes through in order to attract your attention again, and their pathetic crumbling when they're consistently blanked. As others have said, people do see them for what they are; sad, angry, and damaged in some way; if they didn't cause such harm, they'd deserve our pity. I'm not at all sure that they can learn from their actions and improve, rather than carrying on and causing more upset to others; I think that depends on what has caused them to be a bully in the first place - low self esteem, victim of bullying behaviours themselves, etc.
Last weekend, in Rutland, the first statue in Britain of the late Elizabeth II was unveiled.