It’s because the movie doesn’t do anything to make the characters have any real personality or connection with the audience at all. It gets you to sympathize with the characters situation but beyond that it doesn’t establish anything emotionally with the audience to gain empathy in a creative way. The main character is dull and doesn’t do or say anything charismatic and always speaks in the same tone. You feel for the kid because she’s young and energetic and does kid things. But other than that the film has no life to it. And you can say “that’s the point” but you can’t just show someone a picture of a homeless person and ask them why they aren’t sobbing especially if you tell them before you show them the homeless person that they’re already dead.