It is a threat, the key here is that Iran is "tamer" by comparison to the Wahabbi/Salafi funding Sunni nations like, cough, KSA. If Iran really wanted to cause a ton of damage, they could. They could close the strait and really put the screws to Saudi in Yemen, Iraq, and elsewhere and have done/are doing that to a lesser extent now.
Some ok points in the article re reactionary policy under Carter, if we hadn't have backed the Shah and gave him aid, Iran would be more moderate, possibly democratic today. Blowback is a bi*** regardless of how these reporters spin it, I doubt Iran would have changed systems that quickly however, relatively speaking, with no shah.
"Backed the Shah" is something of an understatement.
We (the US and Britain) overthrew the democratic populist and secular government of Iran in favor of a strong monarchy (but weak monarch) who would give us oil rights.
https://en.wikipedia.org/wiki/1953_Iranian_coup_d%27%C3%A9tat
