His is a very idealistic take which weirdly omits that every major example of non-violent protest working to topple a regime involved some foreign super power spending trillions of dollars to wage very much violent wars for the purpose. The insight that he's missing in so many words is that you need to crack the door open just enough for a foreign (super)power to want to come barging in for some reason. Non-violent protests might work as good optics for this, but good optics don't launch rockets on the enemy.

> there are very obviously regimes in the world that have rendered themselves more-or-less immune to non-violent protest.

This sounds like a cop-out to the original blanket statement, or at least this is how I interpret it from your earlier quote. Regimes copy methodologies from others wherever possible and learn from failure to coup-proof themselves faster than the population can keep up. This is why most authoritarian regimes have endured for so long despite many being otherwise failed states, and almost always need some sort of external covert or military intervention to tip the scales.

It's like saying that you can hit the target every time by just meditating. And having a professional take the shot for you.