The legal precedent for gaining the ability to ban content under the guise of preventing the dissemination of “obscenity” allows the future banning of “obscene” political opinions and “obscene” dissent.

Once the “obscene” political content is banned, the language will change to “offensive”.

After “offensive” content is banned, then the language will change to “inappropriate”.

After “inappropriate”, the language will change to “oppositional”.

If you believe this is a “slippery slope” fallacy, then as a counterpoint, I would refer to the actual history of the term “politically correct”:

In the early-to-mid 20th century, the phrase politically correct was used to describe strict adherence to a range of ideological orthodoxies within politics. In 1934, The New York Times reported that Nazi Germany was granting reporting permits “only to pure ‘Aryans’ whose opinions are politically correct”.[5]

The term political correctness first appeared in Marxist–Leninist vocabulary following the Russian Revolution of 1917. At that time, it was used to describe strict adherence to the policies and principles of the Communist Party of the Soviet Union, that is, the party line.[24] Later in the United States, the phrase came to be associated with accusations of dogmatism in debates between communists and socialists. According to American educator Herbert Kohl, writing about debates in New York in the late 1940s and early 1950s.

The term “politically correct” was used disparagingly, to refer to someone whose loyalty to the CP line overrode compassion, and led to bad politics. It was used by Socialists against Communists, and was meant to separate out Socialists who believed in egalitarian moral ideas from dogmatic Communists who would advocate and defend party positions regardless of their moral substance.

— “Uncommon Differences”, The Lion and the Unicorn[4]