Strong ideologies generate enthusiasm, build momentum, evolve the existing social mores to be compatible with the tenets of the ideology, which ultimately starve the losing ideologies of adherents.
If it's a marketplace of ideas, the current situation is equivalent to monopolies stamping on startups to prevent them from ever becoming competitors. An actual marketplace of ideas would work without censorship in the first place, like it used to. Note that most minorities right now who obtained civil rights would never have been able to claim them had they be silenced from the get go.
The fundamental problem is that truth and lies don't operate on the same playing field. If we can make an assumption that the game is being played fairly within the marketplace of ideas (people are being reasonable and accepting rational arguments), then the marketplace works as intended. If certain actors are subverting that system by design, then you cannot have an unmoderated idea-sphere, unfortunately. Studying some Nazi and Communist propaganda techniques should certainly convince you of that (and how effective they are when applied against a gullible populace).
There is no good solution to this, unfortunately. Once a radical movement takes over the idea-sphere moderation and certain censorship is sadly inevitable & needed. Something akin to Denazification in post WWII Germany (which specifically and forcefully suppressed any Nazi ideology from the mainstream)
Just remember that we live in a world where a subset of people genuinely believed Obama is a Stalinist. Once you define whatever is beyond the pale, people will just shove everything they don’t like into that bucket.
But these times do come. Congress was attacked. Threats need to be identified, and quickly.
Should society have said “no further?”
Red-caps, on the other hand...
Perhaps there is a situation where a society says "no further" and is correct to actively shun a political stance. In fact, that's been true in the US for decades... It's real hard to be a KKK chapter without pulling a lot of FBI scrutiny.