I think there are people very funny and with a lot of free time. I'm absolutely sure all these crypto-animals don’t exist.
In my opinion, people who do these films, report the sightings, show some trails, …etc, actually they falsify evidences to prove one theory or some belief.
I don't know which reasons they have to do all these stuff. Maybe they are looking for notoriety, or perhaps they are laughing of us.