>>13063185It is in the pseudopigrapha or apocrapha (lists of books not included in the bible) possibly by mistake. During the early establishment of the christian churches only priests would have the ability and right to read from the bible, they were rather... protectionist of it. Communications across the world not being what they are today(!) it is possible that certain books of the biblical cannon were withheld and reserved for priestly knowledge rather than preached from. At the same time as it was being decided which books would be used it could be that the Book of Enoch was ordered to be reserved for clergy but over time this was forgotten (lore being largely oral) and it simply ended up being considered pseudopigraphal (I believe thats the list it is on, if i recall correctly) because it wasn’t used for sermons.
This is speculative. Nobody really knows the answer to your question so any replies you get are speculation.
