If you think of the Overton Window as a multidimensional space with multiple axes, RMS does occupy a location close to (although perhaps not exactly at) one or another edge of it. Regardless of whether he is wrong or right, he has done a great deal of work stretching the edges of, and drawing attention to, the part of the Overton Window that he occupies. In fact, it's the whole point of the Overton Window argument that even wrong views can often be useful in the grand scheme of things. So I don't think your exceptions to GP's argument are valid.
Also, lots of people have hopelessly romantic views about the group to which they belong (or used to belong). At least in that respect, RMS is not unique at all. But the fact that he falls prey to this common error is not very relevant when we ask whether it is indeed "evil" to make proprietary software, or any other current issue that RMS rants about. (We don't evaluate Peter Thiel's startup advice on the basis of his odd philosophical commitments, do we?)
