Well then, let me convince you otherwise. The first example that came to mind for me actually wasn't the Vahki animations, but the giant poster of Turaga Dume that Matau smacks into the first time he tries to fly in LoMN. It's highly reminiscent of "Big Brother" propaganda from 1984. Dume using the Matoran's trust in him to get them to go in the sleep pods also seems in-line with something that would happen in an Orwellian dystopia. (Typically, common citizens in those stories implicitly trust the Big Brother figure and will do or believe anything he says no matter how obviously wrong of false it is.)
As for the Vahki themselves, they were portrayed as a brutal and oppressive force consistently throughout Bionicle media. Just reading the following quotes from the BS01 Vahki page gives the impression that they employed disproportionate punishments and had little accountability for their actions:
"I asked a Vahki something once. I spent the next month scrubbing molten protodermis feeder tubes... with my mask."
— Vakama, Disks of Danger
"Vahki don't knock. They smash doors down. And they keep smashing them down until they find the one you're hiding behind."
— Nuju, Mystery of Metru Nui
This is completely in line with the way police behave in 1984 and similar stories. (One of my favorite examples is from the movie Brazil, where the police arrest and kill a man over a minor infraction he didn't commit--they only thought it was him because of a typographical error.)
Lastly, the elite Vahki (Kranua and Kraahu) were likened in Maze of Shadows to smashing an insect with a boulder, i.e., they were excessively powerful and were used more for intimidation than any practical purpose. That's the kind of tactic you'd expect to see in a creepy dictatorship, not a paradise like Metru Nui was supposed to be on the surface.