Empathy is a trait that almost all individuals of many mammal species possess. Lethal intra-species violence is also a behaviour observed in many (all, i'd guess) of those same species.

Individuals, their peers, their social networks, their identities, institutions and the specific situation all influence behaviour. When those line up one way, we do a murder. A different configuration and we do a cuddle.

It makes no sense to suggest that humans are either inherently good or bad - those are artificial concepts that don't even have a fixed meaning within a single human identity group. At the end of the day we're just organisms exhibit behaviours to meet needs.