One thing I didn't see mentioned in the article is that loud restaurants can provide diners with a sense of privacy. In a sea of noise your conversation will easily be drowned out before reaching others. Additionally, more ambient noise means less chances of being irritated by other diners.
It also means I can't understand my wife when she speaks. It is bad enough at home with my kids yelling at the top of their lungs (any ideas on how to break them of this?), when we go out it is impossible.
separate them when play becomes loud. take away toys etc. restore peace, give the toys back.
they will scream and fight it a lot the first few time, but if you keep a constant, predictable and strict response they'll get the idea, eventually, that they need to play in acceptable ways.
also make it clear that it only applies in specific time/places (evening, home, public indoor building) and where it's acceptable (afternoons, parks, etc)