Isn't the intent of the BSD license specifically to refrain from dictating what licenses downstream users may add to their derived works? If you're okay with a

Isn't the intent of the BSD license specifically to refrain from dictating what licenses downstream users may add to their derived works? If you're okay with a downstream user making a fully "all rights reserved" proprietary product incorporating your code, I don't see how you could be against that same downstream user open-sourcing the resulting product under the GPL. In what sense would it be more free for them to keep it fully proprietary and not release it under the GPL? I can see an argument that BSD-licensing any derived works so they can go back to the original project under the original license is the friendly thing to do. But then you would frown at both GPL and proprietary downstream licensees, since neither one is doing the friendly thing (in this definition of "friendly") and BSD-licensing their contributions.