Its a good question, and a difficult one. First off if my memory serves me well, when a Wetherspoons opened near me some years back now, and if you like first came on the stage as a pub chain, they promoted cheap beer/drinks, and in my view in turn promoted heavy drinking. That said I don't believe that young children should be exposed to such adult activities in pubs, even if their parents are in control, there is sure to me some inside that pub that a child will witness out of control. When pubs first allowed children in, it was providing it was for family sit down meal celebration, they themselves have allowed it to get beyond that to a certain degree.
Conclusion, they should provide a family room/ area, or keep children out of the drunken experience.