How can anyone ever make fun of my grandma's death?

My grandma ped away yesterday. Long story short I feel very heart-broken and i was very close with her. So shortly after I heard the news my one friend called me and she wanted to know if I wanted to go to the mall. I told her what happened about my grandma and people were shouting and i'm guessing her brother. They said really mean things like " who cares about grandmas" "why is she crying" "My grandma ped away and you don't see me crying" and stuff like that. My friend kept saying shut up. But yeah I still feel terrible about this and I am in complete shock. So what do you think about these people? I cant stop crying and I miss her so much. I hate those trashy people and those low lifes. :( Help.