I believe the official statement from Iran was that it was shot down by human error.

you're probably right -- but the fact that a missile can fire automatically with either 1): inaccurate confidence in the target being what they think it is or 2) an improper confidence threshold allowing for the misclassification of an airliner as a missile, is pretty scary.

One likes to think that automatic missiles should be fairly accurate and confident in their assessments.

My question i've wondered : was the sensitivity deliberately set very high so as to provide counter-attacks no matter what? If that's the case, isn't it more than accidental?

As others mentioned, it was not an automatic attack; humans were in the loop. Even with humans in the loop. I think it is fair to say that sensitivity was set very high; the only difference is that it is much harder to control high sensitive humans are.

Regardless of that, keep in mind that this happened hours after Iran bombed military bases of the country that runs the worlds largest airforce, and days after said military bombed their general.

Under these circumstances, it is entirely reasonable, normal, and expected that Iran would set their sensitivities to very high. It is also expected that doing so greatly increases the risk of an accident, which is why countries only do it when they have extra reason to suspect an attack is likely. The downside of a false negative is not 0. It is that who-knows-what gets bombed, and who-knows-how-many people die, causing who-knows-how-much damage to the country and its ability to defend itself in the future.

This situation is also how wars start. We got lucky that the mistake seems to be such that the big players (eg. the US) are willing to let this go as an accident and let hostilities return to their normal simmer.

If a strike aircraft were that close to a sensitive military installation (by accounts: missile R&D facility) then it could launch weapons at any second.

There likely wasn't "human-scale" time to confirm identity. And specifically against a US adversary with stealth technology, it would make sense to have automated air defense systems on a hair trigger and human air defense systems with extremely liberal RoE.

What seems like it should have happened is that the international airport grounded all outbound traffic and parked all non-emergency inbound traffic in holding, until such time as Iranian air defenses could relax their posture to guarantee safety.

> extremely liberal RoE

For anyone unfamiliar with the term, "RoE" stands for "Rules of Engagement".

https://en.wikipedia.org/wiki/Rules_of_engagement

I've wondered if this flight was the first departing flight for the day at 6:15 AM, so the first radar track headed towards the R&D facility and thus the "scenario fulfillment" they'd been waiting for all night (as mentioned by another poster).

Anti aircraft missiles are not automatically fired and any claims that they are are incorrect.

The warning system is automatic, but it is a human (in this case on heightened alert) that pulled the trigger.

If you’re expecting a lion to jump out of the bushes and you see the bushes rustling, do you wait to make sure or do you run?

Of course you run.

And don’t forget there is a long history of using civilian craft to sneak military things in and out of warzones. Even using hospital ships to transfer munitions.

Possibly. Though surely someone (or some algorithm) in the decision chain finds it odd that the enemy bomber takes off from their own countries airfield.

You don't usually see the take off on radar, especially not with high terrain around.

Western airport radar has gotten pretty good at picking up a plane within 2 miles from the runway but that's if it's specifically designed for it and positioned at the airport.

So some mobile missile launcher array would see the plane pop up a lot later. Someone sitting at the screen with their finger on the trigger could be startled by the first flight of the day and launch.