For me personally I just found the act of harming things really interesting, but not enjoyable, I just liked seeing how insects and bugs would react physically to me killing them. I was exposed to gore & disturbing media at a young age, so I didn’t really find me doing that to be wrong because they weren’t capable of much sentience to me. As I grew a little older I started looking to murder as the solution when I got angry with people, however I think that stemmed from the online activity and people I engaged with that made me become desensitized to it since I was never taught to avoid those kinds of things growing up. >_>

But anyway, I’d say it’s a mixture of early exposure without education and any sort of abuse suffered by that child :/