It's very hard for humans, much less algorithms, to quickly distinguish marginalized speech of the legitimate, unpopular, thought-leading, high-integrity from conspiracy theorist, utopian, pipe-dream, violence-advocating, mystical nonsense without a deep evaluation of a large sample of content, including understanding satire, snark and comedy. Jimmy Dore, Chris Hedges, Phil Donahue come to mind as marginalized, reliable sources.

Maybe some obvious topics can be blacklisted if they're repeatedly, seriously mentioned like chemtrails, anti-fluoridation, anti-vaxx, zero-point energy, pizzagate and antisemitic conspiracy theories... and an appeal for those who get caught up in a comedy refrain.