"That...is a very good question." He doesn't jump into answering right away, either, thinking for a moment rather than trying to do it all from the jump.

"One aspect of it is scale, power. People can do unkind things, yes, certainly. There are large magical workings that can be as destructive as a demon attack. But it is much more work for a human to do acts, kind or unkind, like the goddesses or the demons can."

He pauses, adjusting his grip on the logs he's carrying. Normally, he'd be talking with his hands here. "And part of that is that it's wrapped up in their nature. No person is entirely good or entirely evil; we are works in progress who make choices. People do unkind things because it benefits them in material ways, like money or status. Demons do it because they enjoy it, because it feeds them, because it makes them powerful. They are emboldened by making the world a worse place to live in and prey on the suffering and cruelty of mortal people. Similarly, our Mothers are the heart of the planet, which is full of love for all the things living on it. Their nature is to create and preserve, and that's what they do for us."