Complex and multi-layered? Probably not. The commies helped undermine the Shah and get Khomeini in there to hurt the USA and Israel; pretty simple. The global communists continue to aid the Islamic Republic any chance they get, for the same purpose.
Yes, commies and islamists were often called by the Shah as "the alliance of reds and blacks". Back then Iran had the USSR (Reds) who were constantly agitating in northern parts of Iran through certain Iranian groups.
Interestingly, while the reds were hated by the Shah and kept mostly in check to stop their agitation, the blacks (islamists), were largely left alone. However, there was much more than that to the so-called revolution. A rapid rise in the middle-class. A rapid propelling of society (which wasn't entirely ready) neither for a "western style democracy" nor for entire social freedoms. And so many other important points.
To the Shah's credit, he was no "bastard" and certainly "no American servant or bastard". He was a true patriot. He along with his father before him, and the Shah's wife, the Empress, tried to bring Iran back from the depths of, basically, social and economic despair well into the mid 20th century as it was at that time. They succeeded in many ways, even if they had to bring some people along kicking & screaming. Education and health as well; all in all no insignificant feat, but most challenging.
I can't go into it any depth right now as I'm pressed for time. But it certainly wasn't simply because of the commies or the Islamists, nor because of human rights or democracy that the revolution happened. So many other factors all coming together at that time to make that disaster happen.
All I can say at this time is that to be fair to what the Shah and his father incredibly achieved in just under 50 years, one must look at where Iran was just before the Shah's father took over - that's just one clue.
It is most unfortunate that Americans constantly think that their form of government or way of life/thinking can be replicated in a few years in another country, which has a completely different culture, social norms, religion, history and so on..
These things are processes (not products one can simply install). Processes that take time, long time, and need to be adapted to suit local needs, and often gradually introduced to be embedded. More later, when I got time.