This is not the whole truth; it's an excerpt from Ashcroft vs Free Speech Coalition, which was a case in which it was decided that fictional depictions of minors that don't exist nude or engaged in sexual acts is protected speech under 1A. If anything, its placement seems even tongue-in-cheek; many other countries do not have as thorough free speech protections, and such material is outright illegal.
The "Twitter users" mentioned in the article likley refers to Sh0eonhead who has a history of stirring up controversy around child sexualization with very little evidence, only insinuation and conspiracy style thinking. She's figured out that the one thing that unites the political spectrum is the mere hint of child sexualization and it's being milked for all it is. We saw similar last year, with the 'Cuties' debacle, which was also based on mere insinuation and conspiracy.
Truly a nothingburger story, like most stories based off a few tweets.