I am confuse about a thing I read recently

It's art, so it's subjective. If the person who made something you like is shitty to the point that it starts effecting how you view that art that you like, that's valid. Don't let this book convince you that you *have* to disentangle the artist from the art. Death of the author is a real thing, and works can be interpreted as independent entities, but that's not the only way to look at something.

The example I always refer back to is Heidegger, a widely read and admired philosopher who also happened to be a literal Nazi. People often are able to disentangle his (oft times very visionary) work from his fascist tendencies, but there are some thousands and currents within his oeuvre that jibe really well with fascism and that makes me super uncomfortable, and colors the rest of his work for me to the point where I actively avoid it. Is that "stupid"? Maybe, and I'm not about to say that everything Heidegger wrote was "wrong" just because he was a Nazi, but that sure as hell doesn't mean I have to *like* it, either.

Shitty people often have parts of their personhood which are genuine and capable of being appreciated by everyone. Of course, a shitty person who is an artist isn't going to generally limit their art to reflecting these pieces of their soul. It happens somewhat frequently, though, that the core of a work is decent, even if the shitty author's shittiness are present somewhere in the periphery. However, a piece of art should be judged on its own merits and not necessarily with the author.