This a very interesting discussion about GPL law suits and GPL enforcement. The main point of debate is whether to use law suits to enforce GPL or not. Both of the parties agree that having upstream contributions and user freedoms are important but disagree about the particular methods to pursue that goal. The side which pushes for law suits or threats argue that otherwise companies won't comply, we don't get the code back and users loose on freedom. The other side argues that law suits or their threats turn companies into law suits turn companies into enemies. They are less likely to coorperate, meaning worse software. Instead the way should be through internal negotiations, and changing the culture from inside, companies eventually do contribute upstream they also benifit from it and also because the law requires them to.
My personal opinion is that GPL is important, and the possibility of existance of a law suit. If a company is going very antagonistic there needs to be a law suits because otherwise when the companies know that no one realistic change of law suit then GPL is powerless. Stallman himself gave examples of cases where they were able to get GPL compliance simply about asking companies to do and telling them that they are legally required to do so. So to me the question is really about threshold, not the fact that they should be law suit or not,
Anyway as Linus says it is often easier to change things by working with your opponents rathan working against them but against them should appear like a realistic senario when things don't work out.