I don't know how old you are, so perhaps you have good cause to be surprised that Iraq has turned into a chaotic, terrorist training ground.
But back in the day, this was the predicted outcome before the invasion of Iraq.
So at least everyone who was in favor of invading Iraq shoulders some of this.
From shortly after the invasion, here's July 2003 fer ya
In response to the Soviet occupation of Afghanistan (December 1979-February 1989), US presence in the Arabian Peninsula (December 1990), Gulf War I (January 1991) and the US-led coalition occupation of Iraq (March 2003- ___), Islamism grew in strength, size and influence. As a result, virulent and extremist ideologies found greater acceptance, existing Islamist political parties and terrorist groups became more influential, and new Islamist organizations proliferated.
Although US is under severe pressure to withdraw from Saudi Arabia, the US will prefer to remain in the Kingdom because withdrawal after the recent attack will mean defeat in the eyes of its opponents. Nonetheless, US visibility in the Middle East; US assistance to Israel; continued US presence in Iraq will generating wide ranging reactions from the Islamists, both terrorist groups and political parties. Especially after US, Allied, and Coalition intervened in Afghanistan on October 7, 2001, Iraq is an attractive base for Al Qaeda. The Islamists desperately needs a new theater to produce psychologically and physically war-trained Islamists.
US intervention in Iraq has spiked the ideological fuel prolonging the strength, size and life of Islamist political parties and terrorist groups.
Here's a 2006 report. News stories about this report were derided on this board as "for the moonbats"
• The Iraq conflict has become the "cause celebre" for jihadists, breeding a deep resentment of US involvement in the Muslim world and cultivating supporters for the global jihadist movement. Should jihadists leaving Iraq perceive themselves, and be perceived, to have failed, we judge fewer fighters will be inspired to carry on the fight.
We assess that the underlying factors fueling the spread of the movement outweigh its vulnerabilities and are likely to do so for the duration of the timeframe of this Estimate.
• Four underlying factors are fueling the spread of the jihadist movement: (1) Entrenched grievances, such as corruption, injustice, and fear of Western domination, leading to anger, humiliation, and a sense of powerlessness; (2) the Iraq "jihad;" (3) the slow pace of real and sustained economic, social, and political reforms in many Muslim majority nations; and (4) pervasive anti-US sentiment among most Muslims--all of which jihadists exploit.
