Big picture? He says he doesn't want to be objective about Graham because it's not his job to do that, it's his job to just be a boyfriend, which-- okay, I don't agree, but whatever. I could deal with that just fine if he'd recuse himself from any warden-inmate related stuff, but he won't; the dude wants to be completely unobjective and completely involved in everything Will. It's a nasty combination, especially since his official position is that Will is perfect and can do no wrong and nothing is ever his fault. He's also impressionable and traumatized, and Graham is manipulative and traumatized, and the two of them are disturbingly codependent, so there's... that.

This specific incident, Graham killed somebody; I know you know how that went down. It wasn't unprovoked, but it was overkill by a mile. Graham knows this. He's concerned about it, or at least he says he is. He doesn't want it to happen again, he wants to develop other strategies for people being dangerous and threatening around him. But trying to have even just the start of a productive conversation about it involved Bright in the room, jumping in to repeatedly insist that Graham did nothing wrong and encouraging him not to think critically about his reactions and his options. This is after he got the full story, and after Graham repeatedly made it clear that he was disturbed by what happened and wanted to prevent it from happening again. Bright knows that Graham beat someone to death, and his first impulse was anger and resentment towards his warden for not patting him on the back and saying "You did good".