A student deemed to deviate from the acceptable was immediately pounced on by the blackshirts, who surrounded the surprised student, pounded their fists on his or her desk, and shouted "Communist!" at them.
Unsurprisingly, after a few examples of this behavior, discussion came to an end as the non-blackshirt students were affraid to speak.
Sadly, this sort of intimidation has frequently worked in history. A recent, if less extreme, example was provided by the Bush administration in the run up to the invasion of Iraq. Anybody who had the temerity to point out that Sadam Hussein had nothing to do with 9/11 or that the evidence that he had weapons of mass destruction was dodgy (to say the best) was immediately called a traitor. When it turned out these things were not true (which was pretty obvious all along to those of us practiced in the evaluation of evidence), were the skeptics thanked? Of course not. The closest we got to that was some of the neocons admitting "we drank the kool-aid." As if everybody had believed the wrong things. No, just the circle of people who only listened to each other (and in this case, Fox News). Outside opinions bounced off a thick wall of cognitive dissonance.
Science is not immune from this sort of sociology. Recently (in early 2013), there was an attempt to censor the blog Dark Matter Crisis. Simply by making the unwarranted assertion that the subject was unscientific, an accusation on twitter led to the temporary shut down of this blog. The same person who made this unfounded criticism has repeatedly called me a liar on twitter, and aggressively denounced the publication of a story about the successful predictions of MOND in the dwarfs satellite galaxies of Andromeda. Another of this cadre of cosmic blachsirts (who went by the handle ialsoagree on the Time website) agressively policed the comments on this story, persistently asserting - usually incorrectly - that MOND could not explain pretty much anything. S/he seemed particularly obsessed with gravitational lensing which the GR extension of MOND, TeVeS, does fine.
Now, I don't know these people, and they don't me. If I were a liar, I certainly would have kept my mouth shut about MOND. Instead, I admitted I was wrong to be so sure the answer had to be CDM. (This post about the importance of intellectual honesty has been up for a long time.) I'm confortable admitting I'm wrong - when the evidence says so. That does not appear to be the case for many of MOND's detractors, who generally avoid any discussion of the evidence that favors MOND, prefering to talk about what they're comfortable with (i.e., the evidence that supports LCDM - of which there is plenty, as I've often said myself) and make stuff up when they exceed the boundaries of their knowledge.
I expect that these people would not accept the description of them as cosmic blackshirts. Indeed, I imagine that they see themselves as good guys defending the merit of modern cosmology. They're simply behaving like cosmic blackshirts to achieve that meritorious end. I expect the real blackshirts considered themselves to be the good guys too.
This should be about science. It is not good & evil like some bad '50s flick about cowboys & indians. There are two scientific hypotheses. Both make some outlandish claims. Both have some merit and some real problems. If you think the solution is as simple as black & white, you haven't been paying attention to some important piece of the data.