Warning! There is slang!
"I don’t like stupid books" can be translated as "я не люблю́ тупы́е кни́ги"
"Тупо́й / тупа́я / тупо́е / тупы́е" (obtuse) are coloquial choices for "stupid". But it has a dismissive, arrogant attitude to an object of a conversation. It's rude.
It was stupid = э́то бы́ло глу́по = э́то бы́ло ту́по
But a phrase "сде́лать smth ту́по" has a little bit another meaning = "do it as simply as you can":
"Что сде́лать с этой по́лкой?" = "What I have to do with this shelf?"
"Just hang it on the wall" = "про́сто пове́сь её на сте́ну" (an official choice) = "ту́по пове́сь её на сте́ну" (a colloquial one)
I don't like stupid books, as in the person doesn't like books because they consider books to be stupid in general?
Or, I don't like stupid books, as in the person only doesn't like books that happen to be stupid, and not necessarily every book in existence.
Can someone tell me which interpretation does the original Russian sentence mean? or can it mean both?