Because people help themselves to food, everyone takes like 1/2 meat and then the first six people take 1/2 veg as well. I agree, for single serving meals like sandwiches that are not easily dividable, it makes sense to only have a few vegetarian ones. But those meals are usually at least 60% not-meat for meat-eaters (bread, rice, veggies, whatever). Basically every other meal is not single serving, and the veggie entrees are seen as just another side. It's usually family style.