^ ^ ^ These points.
After an aeon dealing with 7-9 year olds on school trips my sympathies lie with the people who asked to be moved and the owners. The father who wrote the awful review sounds like the "rare, but they are out there" idiots who think that their children can run around willy nilly in a more formal setting.
Taking your children to a restaurant is all part of socialising the little darlings. They aren't too young to be taught proper behaviour. Running around, whether the place is empty or not is not acceptable. It's perfectly possible for 6 year olds to stay in their seats, it's not a playground.
In a 'child-friendly' restaurant that had a play-area a couple of years ago, I saw a waitress trip over a pair of discarded shoes, drop her pile of plates, and knock her front tooth out on a table as she fell. All because the parents allowed the child to leave their shoes and socks in the middle of the floor while they ran off to play in the ball-pit.
The play area has now been removed, and bloody good riddance.