The Orwellian bit comes once the quality gates are in place and get subverted for political means.
But even if that doesn't happen, I disagree strongly. Extremism doesn't need scientific backing and never has. They'll take it if convenient, but they can quite easily justify their actions without it. Truth and critical thinking are the solution, not the cause.
Psychology has always been rife with political fanatics. Since its inception there have been loud cranks using pseudoscience for the express purpose of influencing social policy. It is still happening today. Just look at Joseph H. Manson.
My position is that the problem lies with the listener, not the speaker. I looked up Joseph H. Manson. At a glace that looks like exactly what OP was talking about.
Extremism doesn’t need scientific backing to exist but it does need scientific backing to make the center complacent.
The shooting was a good example but a better example is an extremist takeover of the government buoyed by a complacent public swindled by flimsy science. It’s happened before, it’ll happen again.
Could you not argue that religious teaching should be suppressed since it often stands in opposition to fact, therefore is responsible for misinformation leading to violence? (and let's face it, that's probably pretty hard to argue against)
Banning harmful behavior promoted by religion can be quite productive. Hate speech laws are one example. Barring religiously-affiliated institution from government money is another.
But even if that doesn't happen, I disagree strongly. Extremism doesn't need scientific backing and never has. They'll take it if convenient, but they can quite easily justify their actions without it. Truth and critical thinking are the solution, not the cause.