They didn't believe in a lot of the apocryphal language in those books. A lot of those books weren't written by the people who the book is named after. Some were written in the Second Temple period after the events they are talking about.
They were trying to put books in the bible that they could trace back to the author. Enoch was not written by Enoch. It was written by Jewish scholars back in the Second Temple period. They were trying to give the history of Israel, through the eyes of people that lived in the time, up until the time of Jesus and his disciples.
Most biblical events didn't even take place in Israel. The bible was reconstructed to eliminate any and all traces of Africa and present it as something more palatable to Europeans and Jews. No different to the Vatican having Michaelangelo paint traditional biblical characters as white and no longer Black.