Just an antecdote, my liberal uncle regularly post stuff claiming fox and other conservative outlets are "propaganda" and should be banned, and praises other countries that have supposedly already banned them (I haven't looked up the accuracy of the claim) as "propaganda".
I agree that defining "offensive" speech in order to claim it isn't protected is a direct threat to free speech.
("Propaganda", "hate speech", "anti-science" ect.)
Of course we already have certain limits such as "yelling fire in a movie theatre" (likely to cause an immediate dangerous panic) or making threats of physical violence, so some speech is limited, but based on a more imediate and substantial threat.