Not every character attacks with Negative emotion , fighters with high skill surely won't get ragebaited that easily.
But Cath and Chaos Lancelot are consumed by Malice , it's different with them.
That is not how Diodra’s ability works.
If it were, Diodra would have easily stopped the Perils in the past, given that all of their attacks were driven by an intent to kill.
Diodra’s ability only reflects attacks directed at him by individuals who harbor feelings of hatred and anger toward him.
In Lancelot’s case, he feels nothing toward Diodra.
Lancelot goal is to destroy the world, anyone else is just a victim who evokes nothing more than his own guilt and sorrow.
If you were asked to destroy an anthill, would that mean you harbor feelings of hatred and anger toward every single ant inside it?