The point is Stallman himself would rather see upstream GCC become an inferior tool, or fall in to disuse and obscurity, than act in any way which, on balance, would mostly just enable proprietary software. We're talking about a man here who said (just less than two weeks ago at 31C3) that stealing food to survive, given no third option, was more morally justifiable than writing proprietary code for a living.
The author of this blog clearly doesn't understand this world view because they've set themselves up with a strawman to knock down, assuming it merely boils down to a strategic error on Stallmans part with regard to what is the most effective means by which to ensure the best products out there are FOSS.