Oh no, I totally agree -- I know Harry has yet to learn to agree to disagree (he's still REALLY immature that way). We see hints of it (kind of) in both PoA and GoF (with Ron and Hermione). It's always that if you're opposed to him, you're immediately his enemy, and clearly (if he's got to learn to work with everyone/all the Houses), this is an attitude he's going to have to grow out of.