[deuterio12]

Originally Posted by Zorg

Angron - turned crazy by non-Imperial slave owners. Ignored orders to not put the red nails in his men, turning a lot of them crazy.

Wrong, he still had some shreds of sanity and decency. It's when the emperor arrives and separates him from his companions and then makes him watch as they're butchered that he completely loses it.

Originally Posted by Zorg

Mortarion - Raised by alien (possibly Dark Eldar), which doesn't help, he was betrayed by Typhus who was corrupt from the get-go.

I'll admit I don't know a lot about that one so I'll trust your word.

Originally Posted by Zorg

Magnus - Made deal with Tzeentch before he met the Emperor, fall came due to his breaking of the Emperor's laws.

He broke it because the Emperor needed to be warned. The emperor then thanked him by unleashing Russ on Magnus, thus forcing him to completely turn to chaos or turn in furry food.

Originally Posted by Zorg

Lorgar - Corrupted by Erebus, who never renounced the Chaos worship he had before the Emperor arrived. Also thought he was putting humanity on the path to true enlightenment.

Not really. Lorgar started worshiping the emperor. The emperor rejected that kind of behaviour and claimed there was no such thing as gods (aka a blatant lie). Lorgar then goes to find out that there are indeed gods, and they want to be worshiped, and thus the IoM is being built in lies.

Originally Posted by Zorg

Alpharius - did what he thought was right to stop Chaos in the long run.

The road to hell the warp is filled with good intentions. Joining the side with daemon weapons and daemons however wasn't exactly a very smart choice if you want to fight against chaos.

Originally Posted by Zorg

Fulgrim - hubris combined with naiveté, plain and simple. When he realised he was out of his depth and had made a terrible mistake, a Daemon posessed him.

He also only got that daemonic sword because he insisted on fully exterminating other race just for the evulz, so he never had any traces of good on him.

Originally Posted by Zorg

Horus - was an idiot who was tricked by Chaos and betrayed by his own men into creating the horrible edifice of the modern day Imperium through destroying the works of the Crusade.

Yet the Emperor picked him anyway as the warmaster.

Lo and behold, the first Commander Incopentus in the IoM's history! The emperor is guilty of seting this dangerous standard for the IoM of not bothering to check if the people you're puting in charge are idiots and/or easily trickeable.

Originally Posted by Zorg

The only ones the Imperium could be faulted for (and then only in part) are Curze for being forced into the role of bogeyman given his already damaged psyche from landing in Gotham City a non-Imperial crapsack world.

Fully IoM fault. Curze was actualy doing a fine job of turning that world in a better place, then when he leaves whatever administration forces that were left behind let it get to the old ways.

Originally Posted by Zorg

The other is Peturabo, who basically threw a temper tantrum because he didn't like guard duty and lost it completely when his world rebelled.
Neither of those really have to do with corruption either, just the Primarchs rebelling against their assigned roles.

Most of the traitors turned traitor due to petty jealousies with each other played upon by the corrupted legionnaires, or due to misunderstanding or underestimating chaos (Lorgar and Magnus respectively).
Many of them did things despite the Emperor specifically saying "do not do this thing", which really didn't help matters (Angron, Lorgar, Magnus).

Yet the emperor was completely random on how to deal with those issues:

-Angron performing lobotomies on his troops turning them into bloodthirsty monsters? Let it slide for emperor knows how much time.

-Magnus tries to warn him of his brother's treacheries with magic? Unleash the furry hordes on him!

Originally Posted by Zorg

The lack of understanding of the role of chaos is pretty fundamental, as most of the traitors don't even realise they're working for the Chaos gods until much later. For instance in the end of Nemesis a huge sacrifice is performed with the victims arranged in an eight-pointed star. Some of the watching Sons of Horus don't understand why they're doing it, and are troubled by it.

Lorgar is horrified by what happens to Fulgrim when he discovers the truth, as he thinks the warp powers just want to party
(Aurelian).
Magnus thinks he's smarter than Tzeentch, making a deal he comes to regret after breaking the Emperor's laws (A Thousand Sons).

Please remind me, how exactly is they not knowing what they're doing, and yet doing it anyway, a better thing?

Originally Posted by Zorg

The Emperor himself is guilty of this too, thinking that supressing the knowledge of the warp powers would be enough to stop them - but then again he has to be or the whole story would break down.

And now we've hit the critical point. The history only works if the emperor seriously believes "If I close everybody eyes and ears, chaos can't hurt us!".

And the emperor is the central point of the IoM. Which brings us to

Originally Posted by Zorg

Except their corruption had nothing to do with the Imperium, at least not the Imperium as an institution:

For all effects, the IoM is the emperor. His orders were and are still absolute (if you claim you hear his voice, then you're given high positions instead of being thrown in the loony house). Thus all of the emperor's faults end up reflecting in the IoM. His errors back then echo trough 10.000 years.

Originally Posted by Zorg

Though it's not mentioned much nowadays, some of the older background material relates how the Chaos Legions hate themselves for what they've become, but because they're twisted by chaos they blame the Imperium for letting it happen to them.

And they're actualy right for it. Many of them were put in positions where chaos was indeed the only answer (Lorgar wanted something to worship, Magnus had no other way to try to warn the emperor, Angrom wanted revenge, etc).