Of course he will say that, his job depends on there being patents to work and litigate with.
Yes, let's just ignore his decades of experience in patent law and years of studying patent history that comes with the territory because he has a vested interest. On the other hand, he makes some fairly good points. If we all but abolish the patent system for technology companies they would easily be overtaken by whomever has the largest manufacturing capacity. Ever wonder why Foxcon didn't just grab android and make an iPhone clone? Why be subject to Apple if there are no IP restrictions at all? People bemoan the quandary of the small innovator, and this is a legitimate concern, but it must also be weighed against the benefit patents (software and hardware) confer to large companies who must decide how much to spend on R&D.
Stallman is an activist against tightly controlled intellectual property, copyright and otherwise. That isn't a something to hold against him, it's just a fact that one must consider when listening to his opinions and analysis. Please try to keep that in mind when reading analysis from the other side.