Not all experienced programmers become functional acolytes. See: Ken Thompson, Donald Knuth. They like procedural programming and prefer to model programs with imperative, mutable state, rather than pure functions that map one type to another.
Richard Stallman is known more for his clarity of thinking about individual freedom and its likely abridgements that can arise as a result of using commercial software, than his chops as a coder. I could be mistaken, though.
