In a bit of fairness, I actually emailed Stallman about this a couple years ago and he's a bit more nuanced if you press him on individual things.
For example, I asked him about an app that I was working on, where we were doing things with a BSD license (since the thing we released was proprietary but the core was open-source), and he suggested that we instead re-license it as GPL but with an proprietary exception for only our app.
