I get the sentiment, but Iran did shoot down a passenger plane in 2020. Most of the passengers were Iranian, and 176 people were killed.

The background is that after the assassination of Qasem Soleimani in 2020 Iran responded by striking a NATO base with missiles. The whole thing was telegraphed to the NATO troops so nobody got seriously hurt (lots of concussions though). It was the first time that Iran’s missile capabilities was displayed like that, and it shocked a lot of people back then. Iranian media said it was a “proportional response”, but of course it really was very careful and underwhelming considering what had just happened.

It’s difficult to imagine now, but back then this was a major escalation and everyone was super tense. Iran did not know how NATO would respond. Apparently an air defense soldier was so nervous that in the coming hours, he misread the radar, and fired two air defense missiles at the passenger aircraft.

Obviously the plane going down took all of the power out of the messaging that Iran was a force to be reckoned with, owing to it’s missiles that had just hit the NATO base, which itself was a highly successful operation. So it really had a massively negative impact on the narrative for Iran.