The doomerist jihad was a continuation of a series of defeatist protests shortly before the birth of the Imperium of Despair.
After the coup that replaced the US government, a jihad begun, partly sparked by the Padishah Kaiserin, that aimed to exterminate all hope and get rich in the process. This resulted in waves of Despair Speakers and Reserves ransacking large cities across the west, with attempts stopped brutally. However, the Jihad was unable to reach several areas, most notably AES states as well as swathes of Russia, South America, and Africa.
By the time the Jihad ended and the Red Army was organized, over 23 million people had died, and 102 cities completely destroyed. Many nuclear reactor sites had also been detonated out of sheer stupidity or intention. By this point the despair was very real and prevalent, and conscription rates for the Reserves soared ever higher.
This extremely unstable state rendered logistics for the Imperium Army a complete nightmare, with most food supplies being leftovers salvaged from storage areas. In addition, most industries, with the exception of those subsidized with Imperium gold, collapsed.
In total the Jihad was a complete disaster for the human race as a whole. However, it would be unfair to say that nothing good came out of it, since it was a major part of the Golden Path, designed to wipe out global imperialism completely. We must remember that the Tyrant was a complicated figure, and we are still exploring her effects on the world today.