You're not wrong, but I think there's a very decent way to do loops that spices them up a bit and fakes some variety. It's like adding an extra layer on top of the loop where characters move their heads, torsos, shoulders, hips to vary the thrust, etc. The issue with this particular piece I think, is that it's looped in the most literal sense.
There's not even a slight variation in body movement to help "sell it," which I believe is the core problem. Overall, I still enjoyed it, but I definitely think it could benefit from more variety in the loops and more character movement.