I think that's going to be tricky, because there's nothing to 'get'.
The people at the table create the game world. The people at the table connect the mechanics to the gameworld.
Association or disocciation are matters of choice or preference - they are how you relate to a mechanic, not a property of the mechanic. A distinction Crazy Jerome has already made in this thread but which seems to have been passed over.
So discussion of this 'theory' is, sadly, superfluous. It's 'what I like' dressed up as objectivity - and then pushed as 'roleplaying' while anything else is, according to the essay, not roleplaying. A manifesto for OTW, if you will.
While I totally agree with you, I think the difference is, "associated" mechanics are ones which pre-define the world in such a way that the players at the table are given no choice. Take 3e lock picking as an example.
In 3e lock picking, you must use some form of tool to pick a lock. That's hard wired right into the mechanics. If you do not have something you can use as a tool (even as an improvised tool) you may not pick a lock. Period.
Now, how this applies to non-pickable locks like a chinese puzzle box or a combination lock, the rules are silent on, but, that's a nit pick and it's pretty reasonable to presume that most DM's are not going to tell players they cannot open a combination lock because they don't have picks.
However, the reverse is also true. The players can never try to open a lock unless they satisfy the requirements of the mechanic. I've given the example of a "Fonzie Bump" sort of maneuver my theif character tried in 4e, simply because it was funny and cool and totally fit with the character. The table accepted it and it was a good moment.
But that only becomes possible because 4e skills are not specifically associated. You use the Thievery skill to open a lock in 4e and the only thing the rules tell you is that you open the lock, they don't say how. Makes sense, 4e isn't really concerned with process sim. How is up to the players at the table.
So, yeah, I agree that the reality of the game world is defined by the players, I think there is a certain number of gamers for whom the game world is defined primarily by the mechanics. What sort of spins my wheels is that when confronted with the myriad of contradictions this creates in the game world, I'm told that because it's associated, we can just ignore those contradictions.