I mean, that is a bit of a pedantic point (I don't mean that as a personal attack). The full phrase would be "cities are loud places." The specific things are all human-created machines, processes, actions, etc., and cities have way more people and thus way more of these specific things. I don't get what point the youtube channel is getting at.

The specific things exist in my Jersey Shore hometown, but my current street in Philadelphia is way noisier right now in January than Ocean Ave, thus by extension, the city is a loud place, and the noise is constant. Even 3am is not exactly peaceful on my street.