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.
I’m curious. I totally agree that anyone who sees it as a love story is someone best to stay away from but why is it a dealbreaker for you if they love the book simply because it’s a great book and understand that Humbert Humbert is clearly a villain?