Straight: Norman is usually rude, arrogant, immature, lacking in manners and ill-adjusted along with poor people skills — and surprises everyone when he calls Brandon out on mistreating his friends.
Norman thinks that going along with social norms is for wimps and has a bad habit of loudly discussing his crudest thoughts. Even he finds Brandon's decision to go on a Roaring Rampage of Revenge for some random, relatively small slight to go way overboard.
Norman thinks he's superior simply because he doesn't engage in one kind of disagreeable behaviors, ignoring how he has no problem acting in ways that could reasonably be thought of as disagreeable, if not more.
Norman, in the vein of being an asshole, is also an extremely self-deceptive hypocrite, who never thinks rules could apply to him.
Norman is considered a Jerkass because he is always rude to his teammates and speaks aloud every single bad thought he has about them. This is why he is the first person to call Brandon out, whereas everyone else avoided the issue to be polite.
Norman calls Brandon out in hopes of raising his own esteem in eyes of others.
Zig Zagged: Norman calls Brandon out on his misbehavior or breach of conduct, then in mid-speech turns around and starts presenting Brandon's reasons, good or not, and chastising everyone else for being narrow-minded jerks — to mock Brandon. Others are put off by Norman's hypocrisy and flighty manner of presentation and remark that while Brandon's course of action wasn't exactly laudable, Norman is still worse and thus in no position to judge.
Norman makes no comment on or doesn't care about Brandon's behavior.
Norman looks like he's going to call Brandon out, except that it turns out to be a remark about some completely unrelated matter.
Lampshaded: "I can't believe I agree with him."
Invoked: Norman attempts to draw the attention to what Brandon did.
Other characters say that it doesn't matter if Norman is right, because that doesn't make him any less of an asshole.
"Okay, Brandon did wrong and suddenly I'm supposed to act like a saint? I don't care."
Deconstructed: Norman and Brandon actually have painful history together. Brandon's deed is what pushes Norman overboard.