In a time when many outfits -- and, most importantly, Apple and Google -- are making many things work without copyleft, fundies like RMS are most important because there is a good and big collection of copylefted software that they curate based on it solely.
Oh, I like llvm and clang. And I like the Android runtime. But I am always worried if their non-copyleft status could be a shot in the foot for the Free Software community. Apple, for instance, closed up the Darwin kernel a long time ago.
And I believe in Free Software and what it represents. Not only Open Source as ESR says -- a methodology for open development, reaping the benefits in its "many eyeballs" and other effects --, but Free Software, preserving fundamental freedoms that proprietary software robs us.
So, I support RMS, not because I believe that he is never wrong, but I believe that he brings balance to the world. When things tend do be closed, TPM'd, DRM'd and Tivo-ized, he is the wheel that squeaks louder, warning that the whole machine needs to get a bit of grease.