It means something to me. Why doesn't it mean anything to them?

All these people were supposed to graduate with us. Not move away because they need a fresh start or because their parents have been transferred.  I may not have liked some of these people, but when we first started highschool, I thought, "This is it. these are the people I am gonna be spending the next 5 years with. I probably won't get along with all of them, or even get to know most of them, but we at least have something in commmon. This is our highschool." To me once you've entered our school, you've made a commitment to stay. They owe us something. Why is that so meaningless to other people?