He was not some oracle of technical insight that nobody else had or shared. Many people made such claims long before he did. His free software ideals put him in a very good position to be retroactively proven right about surveillance, because the people who are super into free software and the people who practice real opsec end up looking fairly similar.
I'm not minimizing that he was right, just countering that we all were. And we failed to deliver the message and/or trusted in our government a bit too much. 641A should have been the catalyst. The EFF continues on it to this day. It took Snowden and the proof to get there, and we are still not there. I don't think we even know where the hell "there" is.
Another important thing to remember is had we listened, nothing would have changed. Us heeding Stallman and others wasn't the problem, it was a state actor perpetrating while making it nearly impossible to know about it. It makes us kumbaya a bit, maybe democracy could have fixed it, but all of us were (and are) almost entirely powerless in representative government. Even Joe Biden said as much on VICE the other night, just about a different topic.
Surveillance was going to happen. It was a done deal. The terrorists beat us the second those aircraft hit, because terror has driven us every minute since.