Pretty sure the whole reasoning behind the eagles not taking the ring to Mt doom was because of the nazgul. That's why Gandalf had the whole Hobbits sneak into Mordor plan.
Yeah, not understanding that is a consequence of people not reading the source material, because Tolkien definitely explains exactly why the eagles couldn't do that.
On the other hand, I think it's a valid criticism of the movies that, for all the amazing things he did in that trilogy, Peter Jackson failed to explain something minor that turned out to be a lingering issue for some segment of the wider audience that would consume that adaptation.
That would be an interesting start for a completely different saga.
“Ok, so that plan didn’t work. Like, not even a little bit. Now the whole world is on fire, thanks to our genius shortcut. Any plans how we could fix that?“