I applaud the manager for doing the things he did. Kids can potentally hurt themselves being allowed to run around like that. It was for everyone's benifit that that action was performed by the manager
1) The kids have to learn to behave in situations
2) The parents need to control them
3) The restaurant could have been sued if something happened to the kid
4) Ruining lots of meals. In both ways. If the kid runs into a waitress serving someone's food and the food gets spilled it will get on the guest, and might ruin clothes, phones, etc as well as waste food and wasted food = wasted money.
This is why around here I see more parents getting thier kids a tablet so they can play angry birds while the parents enjoy their meals and both parties are happy.