We've been censoring/banning books, including childrens books, on racial grounds, ( maybe other grounds too? ) in this country since the 1960's/1970's that I know of, probably a lot longer than that but that's books that i'm personally aware of. ( Lady Chatterley's Lover survived in the end
though, lol. )
So banning can be done if there is the political will to do it, as was the case with books containing racial, or perceived racial references, no matter how innocently intended. The trouble with the current fashion/fad of transgenderism is that, imo, political will is wrongly happy to push this ideology, hence books like the one being discussed in this thread not only being published but being pushed and celebrated.
Maybe we just don't realise how many books have been banned/censored, unless like with the books i'm aware of, they were removed from shelves/titles rewritten. Maybe a lot just don't get as far as being sent any further than the literary agent because they don't fit within the rules and we are therefore unaware of their existence.