I find it very hard to understand who's more in charge of this mind: the 7-year old Rin or the "ageless" insane Shion. Rin's a kid but definitely more mature of his age because of being a reincarnated Shion. However, he's still a child, so maybe that's the explanation for his unwillingness to be mature about this whole situation.
Haruhiko is clearly suffering with his own past, but I highly doubt, given his character, that he'd be unwilling to apologize for everything that happened. Sure, it's very possible that Shion wouldn't ever forgive him for doing what he did. But, it's also very immature to act upon that in this fashion.
It's hard for me to be empathetic to Shion if his tendencies are being like this, but it just sucks to be Rin in general.
Even worse off, how much can our mature Rin understand of the weight and magnitude of Eternal Outcast Shion? When a person goes mentally insane, is there even an end to the darkness of madness within his mind?
Where does "Rin" end and "Shion" begin? They're one in the same, but still different people with different experiences.