Very true - apart from the Facebook app which still does background stuff and eats battery, even with Background App Refresh disabled.
I wish Facebook would sort it out.
Unfortunately, the background app refresh setting doesn't really do what a lot of people think it does: Turning it on basically means iOS will wake the app up periodically so it can perform background tasks. The intention is iOS learns your usage patterns and if, for example, you always read the news at around 7:00am it may start waking the news app up a few minutes before so it can refresh the data and it's ready for you at 7:00am
Turning it off will just stop that behaviour and will do nothing to stop apps that want to from actually using data or processor in the background all the time if they use one of the approved methods.
The biggest issue is apps that mis-use APIs such as audio or navigation to allow themselves to keep running in the background and there's not really any technological way to stop this as there are valid uses for them - for example, you wouldn't want spotify being put to sleep while you're listening to music!
It's really down to the app developers to stop trying to game the system (and for Apple to come down on them when they do) and respect users' devices a bit more...