I'd disagree with this part pretty strongly. What clear parameters are you thinking of, besides "get rid of my enemies"? Can you formulate a "no endorsing violence" policy that keeps the current protests/riots while banning Trump's latest idiocy, or one for "no racial discrimination" that keeps White Fragility and bans "they're not sending their best... Murderers, rapists" or similar? That kicks off Infowars or Richard Spencer while leaving Malcolm X or Ta-Nehisi Coates? Sure, the political right tends to cross those lines further - but it's often a case of degree and direction, not kind.
I think it's either a really hard line to draw in a viewpoint-neutral fashion, or a huge political fight. (Whether you choose to ban Trump without the Left, or you try to ban both, people will be furious)