A reason why mammoths could once be considered a endangerd species?

Well they are now extinct, so there was a time they were in danger of becoming extinct, thus once they were an endangered species. I guess all extinct species were once endangered. It's confusing though because at that time the concept didn't exist so there was no one to think of them as endangered.

Which is sort of like the semantic question "If a tree fall in the wilderness and there is no one to hear it, does it make a sound."