In my view veggie meals must not be compulsory but they could be a great and good change for teens' health as the present menus (in my school anyway) are not what you can call balanced. I renounced eating at the canteen first for this reason.
More fruit and vegetables would be so much healthier than meat in sauce with French fries !! I'd love to experience the veggie alternative at school, as I am convinced it is a public health matter !