I don't see where you've read that they accepted donations. Every article and Reddit post I find says they didn't? It was indeed releasing on Steam for free, but I don't know if they had contacted LEGO before doing so.

Also, this wasn't the only Bionicle game that LEGO had endorsed, Quest for Mata Nui too, which makes this even more of a heel-turn. They won't have to shut down that one, though: the team went silent and then the main dev passed away.