As much I disagree with racists, I believe that a healthy society must allow them to speak.

I tried to find a quote from Dershowitz’s book on defending Nazis but gave up due to paywall.

Toxic is not an objective measure for speech. But like in real life, toxicity depends on the dose. Life doesn’t eliminate toxins, it reduces them to manageable levels (or dies).

There’s also the practical effect that banning is irreversible. Toxicity is not terminal, but banning doesn’t allow for redemption.