It is dog eat dog and expecting fairness is naive. In this case though, if they like you say, they promote those values they should emulate them or they risk being expose for their hypocrisy. I would even suggest, if you don't expose them, you are promoting and supporting their hypocrisy.

When I give something away, I don't expect to be compensated.

You need to ask yourself, and it seems maybe you did but ask why would the provide compensation for something that was freely given to them, they are a profit-making enterprise with possibly shareholders to be accountable to or at least owners who maybe would rather keep the money. You asked yourself and your answer was their values are kindness, fairness and authenticity but are they being unfair, you gave the material to them, they did not cheat you, maybe it is unkind, have to think on that.

If I made a painting and gave it away and the recipient decided to sell it after a while, should I expect that they would share the money they received?

All kind of interesting to think about.

TEK