I hope for the sake of person being interrogated that it is fake but this could be a tactic for intimidating other protestors who are not firmly committed and have other responsibilities in life to worry about.
>I’ve always (and that’s not ranting. I really have) wondered if it was on purpose.
Of course it's on purpose. No one would watch a police procedural drama where the police always lost, were inept, or only won their cases due to corruption or malfeasance, or where the criminals were never caught and cases never resolved. Showing the heroes defeating the villains isn't propaganda, it's just good storytelling.
I'm not sure what western TV dramas have to do with the Chinese government putting people in tiger chairs and forcing confessions out of them over posts on the internet.
Fictional TV shows are hardly comparable to video in the OP.
Public displays of criminals, trials and punishments are not uncommon in China, and serve as a "legal education" for the public.