Very few people are too smart to write compilers. Very very few people make huge personal sacrifice to dedicate their entire lives to the ideology they believe in for the good of the world. RMS is both which is very rare.
Those of us with more "normal" lives can never understand how much RMS gave up for his dream. Is he a weird old man with some unsettling habits? Probably, but that makes him no less of a genius. He could have done anything and he chose to give us GNU.