Matt tries very hard not to show his bias, but everyone does. He's got a preference for high levels of acting and improv, and that's cool, but despite his attempt otherwise, his description of roll-playing (and even "one dimensional" roleplaying) can be easily construed as offensive to those who prefer that style. It's not quite as simple as he tries to make it out to be, but he's on the right track.
There are many levels of roleplaying, with most beginners focusing on the game part of RPG. Most move on to making more in-depth characters on a gradient scale. In general the more detailed the character, the more interactive the player is during roleplay, although this isn't always the case. Each player has their own comfort level of roleplaying, that can't be quantified with a simple 3 (or 4) point scale, because this doesn't take into consideration the personality of the player, let alone character.
IMO roll-playing is a different issue. Roll-playing is playing to the mechanics of the game, where you don't take any action that would require a check unless you're good at it. Roll-players most commonly check their character sheet before making a decision. They can still be roleplaying, but they bias their character by their mechanics, rather than in-game development. Technically there's nothing wrong with this, although I personally feel that not only is it distracting for the game, but that the player is limiting themselves from the full game experience.