| Quote #10
"I'm not doing this for you. I'm doing it because – I don't reckon my dad would've wanted them to become killers – just for you." (19.174)
If there's a common thread uniting all the Harry Potter books it's the idea that doing the right thing isn't always easy. Harry arguably does the right thing here by stopping his father's friends from becoming murderers, but it's a hard to not take revenge against Peter.
| Quote #11
"Think that matters to [Dementors]? They don' care. Long as they've got a couple o' hundred humans stuck with 'em, so they can leech all the happiness out of 'em, they don't give a damn who's guilty an' who's not." (11.2.87)
Since the Dementors are the epitome of bad in Book 3, it stands to reason that they would not pay attention to pesky distinctions like "guilt" and "innocence."