As long as he wasn't the leader of Khaos Brigade(AKA Ophis) he's fine.
Ophis can't be forgiven for being the leader of the terrorist organization. Would Hitler be forgiven? And remember that the supernatural world at large still believes that Ophis is the one at top. Why do you think her existence is a secret?
But getting back on topic, looks like Euclid is going full-out siscon. Guess that's where Sirzechs and Serafall got it from.
