While I agree with most of the author's points about the baneful effects of the "infinite fringe", there would be some good it in to. The past as he describes it had mechanisms for crazy to die out naturally
If a ludicrous idea started building momentum, the ringleader and their affiliates would get pushed out of an organization, then another one, and another one, before being deemed so poisonous that society in general would exile them to some tract of rural land to farm beets and / or start a cult. If they were still interested in spreading their ideas, their options were limited to the physical media they could afford to purchase — a monthly pamphlet sent through the mail, a ham radio, or a sign on the side of the road. Barricaded from the tightly controlled mass communication networks of print distribution and broadcast signals that informed the nation and the leaders they chose, they were forever stuck on the fringes.
That was where “crazy” used to die.
In today's world that is no longer the case, an infinite number of crazy ideas could find a place in social media and there are tools to amplify the messaging or morph it into new and novel forms of lunacy that could not have germinated in the past. This is akin to a world where viruses run amok and there are no medications to fight them. There are many of them, they shape-shift and mutate to increase their odds of survival. The most pernicious (and tenacious)ones make it but many others don't. May if some absolutely crazy fringe idea is fed and cared for enough for it to become mainstream, its worth looking into the energies that feed it instead of bemoaning the fact that it has learned to survive and be heard by all.