I’ll go with the low-hanging fruit: Mein Kampf. I’ve read it, cover to cover. As a piece of propaganda, it’s good. As an example of good writing? Absolutely not (though I will admit I have only read it in translation). Oh, and the whole fascist, racist, and generally shitty worldview of the author that he infuses into the text. And the fact that the author is literally Hitler. You 5-star that book? You’re a Nazi. Period. And as a Jewish person, I don’t look too kindly on them.
Even the author preferred his second book to it and recognized how juvenile that attempt was, but the other never really got the same notoriety. The whole mini genre of self-insert neo-Nazi revenge fantasy that was published in the '90s by Resistance Books was pretty cringe. (Several other books that tried to be similar to this but managed to be even worse including at least one god-awful sci-fi version).
The first rule of writing is to know your audience so if you’re courting a bunch of bigots by writing a bunch of racist nonsense I’m not the least bit surprised that “juvenile” is what they felt drawn to…