Quote Originally Posted by Lacuna Caster View Post
If you had some reliable method of screening the exceptions, sure. I mean sure, this is D&D, you can always employ Detect spells, but mind flayers are natural spellcasters with genius-level intellects. They can probably work around that problem.

It's not really about revenge so much as it's about risk analysis. I mean, let's say you bump into an illithid who appears to very conscientious about following the proper rules for whose brains they may consume, and is virtuous and upstanding in all his dealings, et cetera. Can you be 100% sure that's an illithid who's genuinely reformed, as opposed to an illithid who's very good at faking reform so they can infiltrate your city, enslave key officials and open the gates to their hungry cousins? Because there's bound to be at least a few of those for every reformed soul, and the cost for making a mistake in this matter is very, very high. I can see a certain level of constructive paranoia on this front being, well, Neutral at least.
There's a difference between being wary of someone and killing them.

the rationnal thing would be to judge the creature [...] on its own merits.