I would hope a driver using FSD or any other system like it would be alert/aware to intervene...but for this video, it looks like they were trying to see how the car would react.
This entirely feels like a manufactured scenario since they simply did not act like a informed driver, and decided to freak out.
If none of this is true, than they are incredibly shitty drivers that were not paying attention to what was happening and let the car cruise through a red light. The exact same scenario would have occurred with a standard 1990 era cruise control system.
"They're a bad person so this must be fake", or maybe they're a bad person which is exactly why they thought doing something like this is okay
Look I'm all for knowing this information, that something like this can happen. But to be clear, in no way do I condone how it was done. This seems reckless for the sake of clicks.