It was more of a mutually instigated engagement. Both regimes thought they would benefit from such an action - which they did = they both stayed in power for quite a long time regardless of the heavy human toll. Neither regime gave a damn about the human loss.
The Iranian people have done well under freedom. The overthrow in 79 wasn't even an overthrow by Iranian people. It was a western-inspired (Carter Admin , ie: Brezenski, Europe, etc..) in order to continue the policy of creating a Green Belt of Islamofascist terrorist states in an effort to contain Communism. Europe also liked this new arragnement as they were better able to deal and exploit the Iranian people with the Mullahs at the helm.
You are right... Green belt theory existed!
Iraq launched massive ground and aerial attacks on Iran right on 21st of September 1980 and the war lasted for 8 years.