I’d say kindness may be naive. It can also come from wisdom.
Or strength.
From a personal experience there’s a learning curve. You start off being kind to everyone. Then people take advantage of your kindness and they get ahead, so you get angry and start being evil, then you realize that’s getting you nowhere. Then you learn to be kind to most people but also know when to be evil.
According to game theory, tit for tat is the most effective long-term strategy.
know when to be evil? i am assuming you meant to say when do we have the right to defend ourselves?
Some popular sayings I’ve smashed together: “Don’t count your omelettes before putting all your eggs in one basket.”
Bonus saying: “We’ll burn that bridge when we come to it.”
A malaphor!
A malaphor is a blend of two or more idioms or phrases into a single expression that ends up being nonsensical, confusing, or amusing.