Iranians made a mistake that they imprisoned US staff - they should just seize all belongings and kick them out of their own country. But one must admit that common fate to spies caught during war - execution (also done by US troops in WW II) was not done on any of them and all returned home eventually.
Of course look at media portrayal of Iran back then and even now, when places like Saudi Arabia are big US friends and you hear no loud critics about them... what a sad, pathetic joke
Since Iran was breaking off relations with the US this wasn't exactly a mistake. To this day, we still do not have normal relations with Iran. Bill Clinton was able to re-establish relations with Vietnam. Obama re-established relations with Cuba (although the Republican Senate refused to confirm an Ambassador). While Obama and Hillary Clinton were able to negotiate with Iran we don't have diplomatic relations.
Mosaddeq was a democratically elected nationalist who toured the US trying to garner support (that he'd never get because of British Petroleum). It's a damned shame we couldn't respect that.
[1] https://news.vice.com/article/cia-helped-produce-top-chef-co...
[2] https://www.theguardian.com/world/2013/aug/19/cia-admits-rol...
As to it being pure CIA propaganda, you'd have to explain more about that.