RMS has a philosophy that users of software should have certain freedoms / rights (use, study & modify, redistribute, distribute). That's the gist of GPL and why he founded GNU. BSD-style license does not guarantee these freedoms more likely it's simply easier not to guarantee those rights ...
What rights do BSD contributors lose? All the community code exists, the community can continue without the commercial changes, the community is not required to use some commercial fork. They lose nothing if some contributor chooses not to give back. Furthermore, users of GPL'd code decide not to give back at times too. They can use some a commercial fork internally and benefit from community work and not give back. Also, various commercial users of BSD code have a pretty good track record of contributing back.
What rights do BSD users lose? **IF** they care about "free software" or access to the source code they can just avoid commercial/closed forks and stick to the community based code.
The GPL does *not* offer greater freedom, it creates restrictions to force behaviors it believes benevolent. Forced benevolence may or may not be a good thing but it is not freedom.
You know yesterday I was researching Milton Friedman on youtube. A very conservative and libertarian economist and a must see if any slashdotter is bored in his interview series as he gives arguments on rights of freedom, individuals, business, and government roles etc.
He advocated getting rid of 5 out of 8 federal departments. The first question was if you were king which would you .... and he said "Stop right there!" Who gives me the right to tell others? The argument went on saying what about your principles of free enterprise and economic benefits? He said if he can't get most people on board to vote for these changes then he is opposed by the principles of freedom even if I am right. He also mentioned what if I am wrong?
The point is freedom is maximized by a limited or non existent role set up by a framework. He calls this the free market capitalism where each other self interests does just that. He believes government should be functioning the same way or any other organization.
So RMS maybe right but he is wrong by enforcing his opinion on others if he truly believes in freedom. Milton would never follow through on his brilliance as freedom is the same in the markets or any organization applying it to others. RMS would argue corporations restrict such freedoms. But really his solution is worse than the problem. I will take Milton Friedmans stance on this by a limited framework where both users and developers do what they will as long as they do not oppose that will on others.
Commercial software in this sense restricted in a sense of the user is willing to pay for a product or service because if the users do not like it the market will produce a competitor. Something RMS does not understand in free market economics.