You explained it just fine marco, and got it exactly right.
Keep in mind, though, the ultimate -- and most important -- reason I complain about the white knuckle tests with liner locks but not with monolocks is because it happens both in tests and in the field. I'm nothing if not an empiricist, I'm not gonna try to rationalize why something will fail or not, I'll test it first. I complain about white knuckle failures with lockbacks, too, for exactly the same reason. Monolocks are unaffected by it; so, apparently, are the axis and rolling lock, and Crawford's top lock.
With a monolock, when you white-knuckle the frame, you are pushing the lock (which is itself part of the frame) into the blade tang. In other words, you are driving the lock to lock itself even harder. Crawford's top lock has the same feature -- the harder you grip the frame, the firmer the lockup becomes. It's a really nice feature.
With a liner lock, when you squeeze hard all the pressure is going against the handle scales, none of it against the liner proper. So all that potential reinforcing energy is being wasted, simply bending the handle scales. As you squeeze further, the flesh of your hand sinks in and around the liner itself. If it sinks in far enough, the lock can back out. This isn't just a theory or a guess or personal prejudice against liner locks -- it's happened to me in use, it's happened to many others in use, I can reproduce it in testing with some knives. And, of course, it makes perfect sense, now that I've explained it, I hope
The white knuckle failures should be very easy to avoid on liner locks. Typically, all the maker needs to do is bury the liner a hair below the level of the scales. Pat Crawford is burying his locks really deep in the scales, and making sure the lock gouges hard against the blade tang, to make doubley sure it won't get this kind of failure. I think he's going farther than he needs to, but I applaude the effort.