Earlier quoted context omitted.
I didn't know 50 Shades of Grey was erotica until the movie trailers started hitting TV. Most guys had no clue about the book other than thinking it was a straight forward romance book. I could make the same claims against other people about how they can't tell the difference between spam and real emails or ad results and real results. I know because I'm consistently around it and I HAVE to know. It takes a level of…
A “straight forward romance book” would still be inappropriate
I'm really thinking you're pushing a bias on the situation. Someone did something potentially nice, but in a lazy ass way. Like getting flowers for someone who is allergic to flowers. The laziness really bit them in the ass. It'd be the same if I told someone I liked horror and they got me Twilight because they heard it was about vampires and werewolves.
That's a situation where you laugh your ass off about it and crack a joke.