Frankly it's somewhat Maoist IME. Foodcrime. Actually I'm sure that the children did NOT pack their own lunches.
I would point out that it is your responsibility to decide what your child eats, not theirs.
I had a similar issue with my son's junior school, as they opposed him riding his bike to school (with me). I asked them if they were now taking responsibility for my son's travel, in which case I would like him to be collected at 08:20 from my house by a suitably qualified person.
At that point they engaged reverse pretty rapidly...

I would point out that it is your responsibility to decide what your child eats, not theirs.
I had a similar issue with my son's junior school, as they opposed him riding his bike to school (with me). I asked them if they were now taking responsibility for my son's travel, in which case I would like him to be collected at 08:20 from my house by a suitably qualified person.

At that point they engaged reverse pretty rapidly...