What an absolute tragedy. Well done to Iran for coming forward, admitting it and expressing their regrets over it. It's a stark cry from the utter denial others have expressed when similar accidents have happened, and astronomically further than when George H. W. Bush proclaimed "I will never apologize for the United States — I don't care what the facts are... I'm not an apologize-for-America kind of guy." when the N…
Ronald Reagan, the actual president at the time, did apologize a few days after the event.
https://www.washingtonpost.com/archive/politics/1988/07/06/r...
If you really want to compare the two events, note that after ~4 hours after the event the US did acknowledge it had shot down the airline. While it did to continue to maintain it wasn't in the wrong, there's a stark difference between that & the multi-day denial of Iran.