You know, they didn't have the privilege of getting on the internet and finding out all about Bigfoot, what it looked like, how it behaved and all that, as you and I can do, as the hoaxers can do.
So the hoaxers recorded the sound of the motors up close, and reused the same clip in every scene, complete with their muttering voices in the background.
Also, despite the Hoaxers consistently drawing attention to their leftist credentials, their terms, not mine, both affairs strike me as in fact quite conservative.