Iran has been seriously short of friends since Trump pulled out of the agreement. EU faceplanted on bypassing Trump, basically clutched their pearls, bleated and ultimately let trade with Iran circle the drain.
I suspect Iran had a vital trade relationship with Russia under the covers that was sufficient incentive to sell some weaponry for valuable consideration.
The Iran regime got its nose out of joint when Ukraine broadcast the evidence of missile hits on their 737 departing Iran.
This all has to do with the regime and not the people who are actively looking for a way to get out from under it.