Your first confusion is conflating 'book banning' with protecting children from explicit materials they've not mature enough to be exposed to, as decided by those children's parents.
A good rule of thumb is 'If it's too explicit for a school board meeting, it's too explicit for an under aged child'.
Your second confusion is that those explicit books are not banned, they are available for purchase just as they they've always been, just not available in those children's school library, so not the same at all.
The liberal's and progressive's continued misrepresentation of these 2 points is clearly grossly mischaracterized to the point of dishonesty, their typical tactic, with the DNC political activists and political propagandists being their accomplices, providing the liberal's and progressive's cover to hide behind and pushing the liberal's and progressive's 'book banning' narrative.
Cast in a larger frame of reference:
The liberal's and progressive's agenda is to destroy the social fabric / culture which presently exists, the one that everyone is familiar with, one which has well served to further the Western world as a whole, and replace it with the social fabric / culture which they want, containing not only the famous rainbows and Unicorns of their utopia (a dystopia in reality), but also containing all the bitterly contested culture war issues that sane people object to and have already rejected. Yet the liberals and progressives are surprised when all the same people object and reject, then resorting smearing them with any number of baseless vile insults. All along their media accomplices only further the same and provide cover.
All as part of the culture war that those same liberals and progressives initiated, and yet the same one they are losing. It is of little wonder why the liberals and progressives are so angry, hate filled, and excessively emotional.
The irony of it all is that these same liberals and progressives claim to have some sort of moral and intellectual high ground, all that unearned and unjustified. <SMH>