AH! Okay, I understand now. That one student that gave away the Chicken Nugget wasn't allowed to eat meat for a set period of time, due to the fact he was fasting. So he gives it to his friend who wanted it so it didn't go to waste, which is entirely sensible.
Now the problem with this is, is that the kid who is fasting is getting school food for free... probably through a program that's federally run. Now! This is illegal due to the fact that the child isn't paying for it so he doesn't have permission to give it away, but the child given it is the one held accountable because he isn't protected by this program. That or an oversight was made, either way... this is the fault of the fact the Principal actually wasted everyone's time instead of, you know, firing the lunch lady and saving money. And the cops are obliged to respond. Now, what adds to this confusion is that apparently they don't have or should have policies on this, like telling the kids why what they're doing is illegal and why the school can get into trouble.
So this is really the fault of two very stupid people - lunch lady and principal - while everyone else has agreed this was a waste of resources and downright baffling. Now watch! More money will be wasted in an investigation of what the hell just happened. Gotta love Bureaucracy, right?