I understand where you're coming from. Schools need to teach those things. But if that's *all* they're going to teach, then they don't even need to *serve* lunch. They can have kids come in for four hours a day and go home, to work, to music lessons, etc.
But if we're going to keep this current model, where kids go for 6 or more hours per day, where most people expect schools to mold their moral and social thinking, then we're going to need to allow them the freedom to interact with each other.
And let me add, when I speak of molding moral and social thinking I mean in the positive kinds of ways in which schools have traditionally done this; e.g., don't steal, don't lie, follow the golden rule, etc.