The second part was simply naive. Please consider game theory.
Yours (and mine) moral is from a society with a functioning police force, rule of law and state violence monopoly. Without that, there is a clan society, where your only security is that others (generally relatives) will revenge you. A form of terror balance. Out moral just doesn't work there, since to avoid violence you have to make people believe you are ready to inflict it.
(I am unaware of a third alternative to state violence monopoly and clan societies. There are obviously places in between, with organized crime (south Italy, Mexico?). Please educate me if I miss something basic?)
Let me take an example:
There is no world police since Obama seems to be abdicating USA's partial role, countries now live in an analogue of a clan society (e.g. do alliances for protection from aggression).
Consider how Russia and China are starting the jingoism garbage again. How do you know other countries/species won't?
tl;dr: Don't take your moral instinct for logic.