Uh, what exactly is wrong with providing vegetarian alternatives in school cafeterias? Vegetarianism is a choice that many people make for a variety of reasons - religious, ethical, health, etc. It doesn’t hurt anyone else and doesn’t really make excesive demands of school cafeteria, IMO.
I say the above as someone who doesn’t mind some vegetarian fare, but still likes meat and seafood.
Because more and more there is not the "option."