If Catalina Island were a cattle or sheep ranch with transplanted coyotes nobody would bat an eye at the landowner removing every coyote on sight. Most ranchers probably want 0 coyote / sq mi for lambing. When you're on the same side as the bleeding heart animal rights activists in LA county, that is pretty much grasping at straws.
FWIW I did watch the documentary and did not find it compelling. The interviews were kind of awkward and cagey. The bit about spotlight counting was an odd thing to get hung up on. The thermal drone dude picked up ~16 deer / sq mi. The spot light
study estimated 5.41 deer / sq km. Pretty close. And density is irrelevant to the discussion so it's not a good argument. The conservancy argued that 0 deer / sq mi is an ideal number for those ceanothus and CDFW ultimately concurred with them.