The problem is that I heard too many times the argument that non-copyleft licenses do not prevent upstream contributions, so they must be sufficient. The argument goes like:
1) GCC is GPL'd, not every company might work with it;
2) LLVM is much better for companies to work with;
3) Don't tell me that hinders upstream contributions, see for example how Apple has contributed a lot to LLVM;
4) Hence, non-copyleft licenses are better.

As has already been argued here, GPL is about downstream recipients. In fact, the GPL by design allows for private modifications, and we care about that. That's software freedom.

Of course, I also care about upstream contribution, development in the open, etc. That's what "open source" is supposedly about.

Thing is: I think we should talk about this, so we can make more obvious to other people what we care about, what software freedom is about, and that non-copyleft licenses sometimes are not sufficient for user software freedom. And discussing these things might help us explain why is that, or why the fact that companies contribute some of their work upstream is not enough to protect users freedom.