I did this as a young kid. I can confirm it was a complete lack of empathy and likely a power thing. It’s something thats haunted me more the older I get, as it should. Moments like this made me realize empathy is something I wanted, so I actively worked on it, and it grew like a muscle. I’d say I’ve improved quite a lot but others can judge that

As far as advice goes, yeah teach em about empathy. While this is also psychopathic behavior, I see equally bad feeling based reasons for being that cruel, the same ones that motivate bullying: power and superiority shit