On your second point, I want to be clear that I'm not defending the Iranian gov't. I disagree with the use of sanctions that disproportionately effect the least powerful in there society, by design. This is compounded by the fact that the reasons for these sanctions are not moral violations, as the US and its allies behave in much the same way, but instead about international power.
Geopolitics is messy. In the end I don't see any other strategy besides war that could force Irans hand. If the choices are 1. Show the world that purposefully funding terrorism goes unpunished 2. war, or 3. sanctions I think sanctions are the choice that provides the greatest amount of utility, even if they do harm many.
I find that very hard to believe, considering the activities of the CIA -- just the ones we know about -- over the last several decades (or, really, since its beginning).
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Side note:
Does selling billions of dollars worth of arms to Saudi Arabia count as sponsoring terrorists?
cf. Jamal Khashoggi, et al.
What about civilians killed by Saudi Arabia with American-made cluster bombs?[0] Do they count?
[0] https://www.hrw.org/news/2016/05/06/yemen-saudis-using-us-cl...
Not quite the same, but anyway.