I don't know that there is much you can do. My disrespect is of the system that won't let kids develop naturally, not the people that are trying to work within it to change it.
This guy is trying to get the kids to invest in it, etc--but because he has external mandates that every kid in his classroom must learn X by time Y, there's really no way to avoid "lowering the framework" on them if you want to keep your job.
So when I said that he "half-gets" it, that was really not my place to say, he may very well want to let everyone go at their own pace, but the external requirements forbid him from implementing that way.
When you let reading happen naturally, for example, some kids don't start until in their teens. Flexible timetables are not really part of the school curriculum. I agree that what he is doing is an improvement, a vast improvement, over a list of problems/worksheets, etc, and I applaud anyone who is working to make what happens in a classroom closer to what would happen in a natural setting with uncoerced learners.
In other words, the answer to "how would I approach this" is that I would let anyone uninterested wander off :).
Ok, let me try a little harder. Maybe have a game where you roll the glass from a fixed starting point and try to get it to knock something over. Have a bunch of different sized glasses, and then after people have played a while ask them what they can say about strategies to pick a glass to hit a particular target. And, seriously this time, I would expect interest to wane as stuff got more complicated, and I would let anyone not interested in going further drop off. But if I did find someone that was interested, I wouldn't have any qualms about either the approach of showing them equations that would work or seeing if they can figure that out on their own. The idea of wrapping paper around the glass and seeing the point of the resulting cone, I really like. Kids could come up with a construction-type approach to make an accurate preditction--trace the outline of the glass, extend the lines until they meet, bingo, the radius.
Having that under their belts, then, later, maybe, when something else comes up with similar triangles, I might say, hey, remember that glass-rolling game? Here's a way you can get the answer on a glass without bothering with the construction.
But I wouldn't expect a large fraction of a randomly-chosen population to be interested in this particular math, any more than I would expect them all to like a particular kind of music. I would be happy to point people to music that they might like based on what I've observed, or even show them things they might not have considered but that with a stretch they may actually start enjoying, and open up a whole new vista to them. It doesn't bother me in the least that some people don't like They Might Be Giants, even though they are practically the best band ever :).
So, yes, I'm happy that people are working to align the people in a coercive situation with the path their brain might take if it were not coerced. I think in the end that will have better outcomes for the coercive classes, and, in an important way, make the coercive situations less coercive (if someone "makes" you go to a class you find intriguing and interesting, after all, the coercion reduces to near mootness). As long as the coercion is standing by outside, though, you are going to find yourself bumping into it all the time, and that's just reality. It was the starkness of that contrast that led me to post--how quickly he had to go from intrigue and interest to imposing the method of solution.
Even when you do have to push everyone in the same direction, I think it's worthwhile to make it as interesting as possible--it can, at least, give them a chance to see that there might be interesting things about math, which is a thought that has literally never entered into many minds. That would be a wonderful step in the right direction.
mike