Before I saw your response I removed this sentence from my post as I realized it was not central to my main point. However, I still agree with it and am happy to explain why.
> wasting my time having to watch people who literally have never heard of something as basic as keyboard shortcuts
First it depends on whether the audience for your product includes people who do not know keyboard shortcuts. If that's not your target audience then the rest of the test may not be valid anyway.
Otherwise, there is utility in forcing yourself to watch your users struggle with your product. The best product developers/owners I know have a bottomless appetite for observing people use their product, even if doing so means deferring the rest of their "full backlog of shit". Perhaps they're less efficient in the short term at churning out lines of code, but the understanding and empathy they develop makes them significantly more effective in the long term.
It's like how expert athletes often watch videos of themselves or competitors (when applicable) to understand the nuances of their play - once you understand something very deeply the small things start to matter more, until they dominate the game.
If you are a master of UI/UX and you are observing a user doesn't go through the paths you've created its an opportunity - you might be able to learn something that would make your approach more successful across a host of different users that up to this point you clearly are not winning the game against.
If you take an antagonistic approach and curse the idiot for making you watch you have not even put on a jersey yet.