For real, the difference between professional captioning and a freelancer who's paid pennies on the word/minute (of film) is night and day. In particular its becime abundantly clear that HBO's criterion collection is captioned by the latter. You have all these absolute classics, but anything in A Bit Of An Accent is "unintelligible." Its like so obnoxiously racist classist etc who doesn't even get an attempt at a caption, too. Really pisses me off.
I haven't been able to find any English-language information about laws or requirements, but every single bit of Chinese media I've ever seen has captions baked in.