I can easily see both sides on this one.
In one way I have little sympathy. It's the same as parents complaining after they show their child a violent anime, that it was a 'cartoon' and so it must be for children - having made that snap judgement without investigating the contents in the slightest.
On the other hand, as the article rightly suggests, there are established conventions in the publishing industry and this book defied them.
They are conventions I personally kinda hate, because they are the reason every Crime paperback looks the same as each other, and every Sci-Fi book is instantly recognisable as that genre on the shelves. But the conventions do exist.
In mass-market publishing terms, sparkly happy cartoon = children.
The publisher and author totally knew what they were doing here and they did it anyway. It's wilfully misleading.
Whether established standards should be enough to absolve a parent of the responsibility to understand what they are giving to their child, though, you decide.
I place the blame squarely on booksellers (mostly Amazon) for this. By refusing to have any sort of consistency or transparency about what kinds of cover content will result in authors being "dungeoned" on their platforms, it essentially forces explicit content to have cover imagery and blurbs that obfuscate the content to such a degree that misunderstandings like this can happen.
Words like "sweltering", "sizzling", "swoonworthy" in combination with "romance" are meant to be a clue that there is sex in the writing, but the cover simply can not be obvious about that without risking the book (and the author's entire account) being unlisted without communication or recourse.
I’m not saying this has never happened but I think this is a sensationalized article meant to get books banned.
These books aren’t sold in the kids section. If someone found it and bought it, they were browsing an adult section.
EDIT: I just spoke to a friend of mine who sells romance books in her shop. It is a bit of a problem, but not because of libraries or places like her shop. It’s places like Walmart or Target that just chuck the book on any old shelf and parents that don’t actually review the book without buying it.
Papa Meat has a hilarious uncut video on his patreon where he reads reviews and excerpts from this and other smut novels.