"Of course there's the problem of where the line should be drawn and who should draw it"

That's not "a problem", that's the only problem.

Of course hatred and bigotry and false scientific claims and calls to violence, etc., are negative and of course we wish they would vanish.

But a Ministry of Truth would be worse.

I am willing to build and maintain mental, emotional and psychological armor against very negative, harmful speech if it helps avoid erecting a Ministry of Truth.