Having read a great number of your posts Celebrim, and acquired a good deal of respect for you, I am going to assume that when you say 'Hogwash' you mean you don't agree with that I have said.
Oh good.

You have actually been reading a great number of my posts, because that's exactly what it means.
Fine; I respect you opinion, now please do the same for me...
I respect your experience just fine. However, I neither require you to respect my opinion, nor can you require me to respect yours. I'm not arguing against your experience. You are having exactly the sort of experience I'd expect you to have and I well believe it. I'm asking you to consider your evaluation of your experience.
My experience is exactly as I wrote it; and no I am NOT talking about culture. The SAME group of gamers playing D&D 3.5 play completely differently than when they play other games, even with the same DM. I also notice that I DM differently when I use different games.
But none of that proves that it isn't culture and quite the contrary, to me it strongly suggests that in fact it is culture that it is the issue. Nothing prevents a single community from having multiple cultural contexts and in fact just a slight bit of reflection will show you that culture is almost always about how to think and behave given a particular context. Take even someone not seriously steeped in say an evangelical Christian culture, and put them in a Church - or a Cathedral - and there will tend to be a conscious or unconscious change in their behavior based on their evaluation of the surroundings. Take that same person and put them in a sports bar on a saturday afternoon while a big ball game is on, and you'll get entirely different set of behaviors. Now, if you are thinking that is a system issue, then you are wrong. Because take the evangelical Christian and put him in the Church, and he might - depending on the cultural tradition he's steeped in - start whooping it up and hollering, whereas you put him in a bar and what you'll likely get is slightly uncomfortable silence. But what's 'appropriate'? It depends on the culture, and not on the building. Aggragate human behavior is almost all about culture.
When your group moves between systems, you change cultural expectations and so you get different games that result. You, as you admit, referee different game systems differently. But that's a choice and its based on inferences you have made about what you are supposed to do in the game space created by the rules. A different set of inferences however would lead to an entirely different game using the very same set of rules. And when those two groups sat down to describe their experiences with the game and their problems with the game, they'd be talking right past each other 90% of the time completely unaware that most of their issues weren't with the rules per say but with the assumptions that they'd made in their own play.
In KotDT, it doesn't matter how many times Steve Jackson revises the rules, it doesn't matter how many different systems that they play, they always get the same game. That's because the culture (hilariously) never changes.
I accept this might not be your experience, but it IS mine.
Fine. Again, I'm not arguing against your experience. I'm sure you've had it. But if our experiences with the same system seem to be highly at odds, doesn't it suggest maybe that some other factor than the system is determining our experience?