I can't agree with this general sentiment. With the exception of completely insane CHANAMEs (always an option), it is very possible to discuss CHANAME's motivation. CHANAME may be brilliant or an idiot, a saint or a monster, but his or her actions ought to make sense from his or her point of view.When it concerns CHARNAME him/herself, I think it's important to remember that he/she is a multitude of different people, so who can really say what it is reasonable for him/her to do? Naturally every CHARNAME won't want to try to redeem Irenicus, no more than every player would want to download this mod in the first place.
As to what that has to do with redeeeming Irenicus...well that's a long argument that has already mostly played out at this stage. If the creators and audience of this mod are happy with the idea that CHANAME must help redeem Irenicus because otherwise he might become a Demon Prince etc... fair enough. An intelligent CHANAME failing to see the problems with that (no way to know that the redemption will work and much easier ways to delay the threat)* is not convincing.
*Note the use of "delay" rather than "nullify", since by that reasoning there is never any way to nullify any threat; any villain can become a greater threat in the afterlife, and good person can fall and become a threat, even feeding all of existence into spheres of anhialtion can't protect us from the terror that is a hostile author...