Ok yeah I get all of that, but who says QA's mindset isn't sufficiently alien enough to be considered insane to the average human.
Edit: [Conflict!] for the [Queen Administrator], [Data] for the [Data] throne!
while we pratically measure insanity relative to our own norms, on a theoretical level it is not a relative quality. whats important is if you take actions or hold beliefs that are contradictory to each other/themselves. IE: if you want to survive but you keep hitting yourself with things and jumping off cliffs, you want money but you keep putting it into a giant money hole and burning it, you belief that somebody/something is good but you don't protect/use it. IE: this is
course, thats only one half of the definition I gave earlier, the other half is the nail in the possablity that QA is already chaos (at least before getting corrupted). which is the fact that being chaos requires that one be literally be made out of insanity or at least heavily influenced as the demons/their cultists are.....but QA definitely is not made out of insanity nor would they follow(some people actually compare the entitys and their shards with the C'tan and I like the comparison)
basically, see:
Chaos - Warhammer 40k - Lexicanum
"Chaos is the limitless ocean of spiritual and emotional energy that defines the Warp. It is a great and raw force of change and power, and is both physically and spiritually corrupting. The most gifted mortals,
psykers, can utilise this energy, thus making them capable of abilities which transcend the laws of the material universe. However, the malevolent power of Chaos can gradually corrupt a psyker, tainting their mind and body. "
and
"The Realm of Chaos was formed as the emotions of mortals (be they anguish, desire, hatred, or pride) pooled together in the
psychic mirror-reality of the
material universe known as
The Warp. Such was the power of these emotions that they eventually formed creatures which, over time, gained sentience, resulting in the birth and rise of the
Gods of Chaos. "
TLDR: chaos is not just a quality that we have given to the chaos faction and chaos is not just a faction that are chaotic, they are LITERALLY CHAOS.....their very flesh is made out of the contradicting beliefs and concepts that everyone collectively holds. part of why tzeetch is extra-insane is because he holds domain over all the contradicting hopes of mortals such as how both sides of a war
hope to win and for the other to lose......and QA is not a warp-creature and thus can only at WORST, get corrupted by chaos which at least so far has not happened. (strictly speaking, the entitys might be foolish/dumb enough to think that chaos is the solution to their ultimate quest....but that doesnt matter as they have not properly met yet anyway)