Comment by ahknight

Kindness is that, yes. Fundamentally, though, it's about being considerate in one's actions so as to not harm others. If someone truly believes that acting a certain way at any point risks their ability to reliably be kind in others, then it's a social kindness to be kind and considerate in all actions.

I'll not reach for the easy response and say "Be kind to the Earth" fails your definition without reaching for pedantry with "the Earth has living things" because the Earth is instead a wet rock that cannot understand kindness, yet we show it.