While students need somewhere to sleep and eat, the cost of doing so on campus are much higher than anywhere else (in my limited experience). For example, the cost of on-campus room and board my junior year was 4x the cost of my off-campus room and board the following year. Some schools don't allow for off-campus housing for some or all students, or still require commuters to purchase a meal plan. So perhaps while it's not sensible to include all room and board costs with the cost of college, it's definitely fair to include some or even most.