The fact is, no matter how bad chaos is, it will never compare to the torment of a day in the life of an imperial citizen.
To live in the imperium is to deny everything that makes you human. It is a living hell, in which there is no release from suffering, it is an eternity of torment that haunts you unto death, and sometimes even beyond the grave.
Chaos is release, release from pain, release from agony, it is the inevitable result of repression, oppression, and corruption.
The imperium did not form in response to chaos, chaos formed in response to the imperium.
After the dust settles and the air clears, the imperium will fall, chaos will set upon itself, and all will be restored to the way it should.
Democracy will return, the warp will stabilize, people will be happy and rejoice once again. Mankind will once again be able to seek peace amongst the stars, no longer forced into the dogmatic, xenophobic and genocidal policies of an empire gone mad.