That's not a superstition, it's just the truth. Psionics is a legitimate field of study in 40k.
No, it isnt at least no really, the warp is not something you cant just tackle in a nerd manner with carefully laid rules because the warp on the whole laught at such issue, it a living thing that move and act on is own were time is not linear and it can transform the mind of people, as malcador said -To understand chaos is to understand insanity.
Even then there is a diferent of knowing and
knowing. the later require tons of willpower and understanding to see the dangerous of chaos and very few can do that.
Like make this clear, you cant clean chaos away, is one of the hard truth of 40k.
I'm largely of the opinion that if the Emperor hadn't done the Great Crusade, those scattered pockets of humanity would have done at least as well in pushing aside the various threats in the galaxy if not better, and they wouldn't have created a massive breeding ground for Chaos through industrial levels of churning out human misery in the process. What's the Imperium going to do to help those people, come in and enforce their existing tyrants rule under thread of orbital bombardment? Steal all their resources and people for a thousand years and then show up 30 years late when an actual invasion happens? Just keep the production distributed locally and have smaller local groups cooperate against larger threats, instead of trying to run everything through a bureaucrats worst nightmare of a system back on Terra.
This is very much false, wolf at the door show exactly this when a dark eldar riding party come to a planet, the planet opose and....well they got bomb and them ride until the wolf save them(the of course the wolf forcefully annex the planet). they will fight each other and eventually some uber polis would come at the top and we dont know if they would do better or worst and there is a moment you need more against a bigger threat. Which they are at least two: Ullanor and Rangandian.
Most of the worst problems with the imperium come 40k are caused by his traitor sons and their impact. Humans and their superstitious nature and half finished plans he couldn't implement before the heresy. Like Admech and the lords of Terra.
This is truth but not the entire truth, the emperor did make mistakes, aside of his handling of the primarch, hiding the truth even from them, his idea that no AI and not Xenos as it all the xenos were orcs or rangandian were bad, even then the biggest issue is that he is too powerfull, appear out of nowhere and destroy everyone he contradict him, which such a power is not surprise people think of him as a good. hell is not surprising there is a cult of our chararter, let just way before we have to deal with our own version of legio divinatus.
Try to be better than the imperium is a worthy goal but a dificult one, we cant just do it by saying "do the same just better"