You're correct that there are smart MBAs, so it might be a bit unfair that "MBA" has become shorthand for something else. But it's not without cause. It's a stereotype with some basis in reality.
The key distinguishing factor to me of MBA-think is a combination of posturing with credentials and cargo cult thinking. The essence of this thought pattern consists of thinking divorced from real-world referents.
A strikingly similar cognitive anti-pattern can be found in the humanities, by the way.
http://en.wikipedia.org/wiki/Sokal_affair
I wonder if this is because business borrowed something rather toxic from the post-1970s "postmodern" intellectual meltdown of the humanities? The worst kind of MBAbabble that I've endured over the years reminds me very much of postmodern literary criticism in its vapid, posturing use of language to hide the fact that the speaker is not actually saying anything.
"Supercalifragilisticexpalidocious! If you say it loud enough you'll always sound precocious!"
A closely related cognitive anti-pattern in computer programming leads to "architecture astronautism," premature generalization, and over-engineering: http://www.codinghorror.com/blog/2004/12/it-came-from-planet...
In stereotypical MBA-think you have people reasoning about businesses without reasoning about the business -- about what the business actually physically does in the real world. So you see something similar to the cargo-cultish application of design patterns in programming. A management practice will be applied because it worked once in business X, but it's being applied to a business with wildly different characteristics.
At no point is an attempt made to actually walk the halls, talk to the boots on the ground, actually ascertain the concrete nature of the business one is managing in order to tie one's thinking to reality.
Finally, there's the ugly aspect: all of this is posturing to justify unjustly high compensation relative to the people who do real work.
Back to programming, I have run into "enterprise architects" who do not know what they're doing and who make more than the people in the organization who do. What they do know how to do is how to sound impressive.
Back to the humanities, it's sort of transparent to me that postmodern psychobabble is a similar sort of impostiture to hide the fact that the people in question are supposed to be cultural vanguards but in reality have less to say than the street graffiti artists who tag up their buildings at night. Personally I'd fire the humanities people and then hang out in the bushes at 2am and offer the clever social critics with spray paint cans a job.
Elon Musk is a great example of someone at the absolute opposite end of the spectrum from stereotypical MBA-think.
He's not Tony Stark. He's not superhuman. What he does do is get his hands dirty. When he founded SpaceX he actually taught himself some bona fide rocket science so he would know what the hell he was talking about. He did a similar thing with Tesla, actually dove into some of the hard problems of electric car design himself so he'd have a clue. I'm sure he spends most of his days doing managerial things and raising money like any executive, but the fact that he's gotten grease on his hands means that when he reasons about his businesses he's reasoning about his businesses and not about abstractions divorced from reality.
His astonishing success at building businesses doing some of the hardest things one could possibly choose to build a business doing can be chalked up, IMHO, almost entirely to the fact that he is a smart guy reasoning about things instead of reasoning about hypothetical things. He does not confuse the map with the territory.