I think the license change is a lousy move, but the software isn’t suddenly behind a new license. New versions will be. If there’s a community behind the software they can fork it.

You’re not entitled to someone else’s work forever just because something was open sourced. I think it’s a bad move, but I’ve no right to expect others to do future work for me. They made it possible for others to carry it on, if they’re willing to do the work.