Air traffic has been flying in & out of Iran and all over the Persian Gulf. Did civilian aviation even know about the military activity by Iran that night? Tipping your hand of your military actions doesn't sound like a strategy.Bad things happen when an air defense network is on "shoot at everything hostile on sight" fire watch. Iran was mobilizing for war, as were we.
Iran is still responsible for what happened, but the plane should have never been allowed to take off in the first place.