Those students will spread the idea as a joke until it reaches a bunch of people who take it seriously and start to organize.

That sounds like a different problem. If people are so weak-minded that they can't be trusted to hear obviously ridiculous ideas, isn't that equivalent to asserting that democracy is doomed to failure? That the majority will only "do the right thing" if some "better" people "guide" their opinions "for their own good"?

Well now you've moved away from criticizing echo chambers and gone to full-blown censorship.

Educated or not, framing is an important part of any arguement. Time and attention is limited so who is allowed to speak in a venue and how long they're given is an implicit endorsement. There's an appeal to authority there in all future arguments ("well I spoke here, what have you done") and regardless of how much education you have refuting a false claim is always an order or magnitude harder than making one.

It's not so much protecting people, is ensuring their mental energies can be put toward productive measures rather than swimming through falsehoods for the sake of it.

>> wouldn't they just laugh

I laughed. Back in 1998 I attended a lecture that I though was about evidence of aliens messing with our DNA. What I got was intelligent design as proof that the bible was literally correct. Most laughed, but many did not. Students believe what they are told. Not all of them all of the time, but a significant percentage will believe anything they hear so long as it reinforces their world view.