The panorama situation is pretty stupid. But the rest of mozillas argument is pretty weak, and their approach of describing it and getting lay people to sign a petition is poor form in imho.
The issue I have with many open source projects is that they use open source as a marketing and free labour tool. The contributors to the open components get essentially nothing, they get to make a slightly wonky product less buggy and more useful, and then the company benefits on this by selling the closed component that the open one depends on ( depends on perhaps not technically but at least from a practical sense).