| Quote #1
But this was for my father's faith
The speaker says that he's been imprisoned because of his "father's faith" – not for anything that he himself either believed or did. How unjust!
| Quote #2
Proud of Persecution's rage; (line 20)
The speaker and his brothers are actually "proud" to be "persecut[ed]" for their beliefs. This is probably a kind of pride that we're meant to admire.
| Quote #3
Dying as their father died,
This is the first and only time that the speaker suggests that the beliefs for which his family has been killed or imprisoned are religious beliefs. Historically, the real "prisoner of Chillon" was imprisoned for political reasons, not religious beliefs (See the "In a Nutshell" section for more). Why might Byron vaguely suggest otherwise here?