What you propose is simple (as in simplistic), but far from easy. Content moderation at scale is extremely difficult, if not impossible. See “Masnick’s Impossibility Theorem.”

Also, deplatforming bigots is difficult and ineffective:

• www.cl.cam.ac.uk/archive/rja14/…/vu2023no.pdf
• theregreview.org/…/mcdonald-the-limits-of-deplatf… (bonus link/spoiler alert: it’s a monopoly issue theregreview.org/…/englebert-a-role-for-antitrust…)