Bombing a hospital is either okay because there might be militants hiding in them. Or it is wrong no matter what.

[Igel]

2. Not according to international law.

There should be some evidence that the occupants have voided the building's protected status, some reason not just, "Maybe there is, maybe there isn't, anything's possible."

But if a hospital, school, or other civilian-use structure is being used for armed, military means, those who have converted it bear the liability for its changed status as a legit military target.

You like the Geneva Conventions, then you like the Geneva Conventions.

The best that Iran said was that they were aiming for a military target "nearby" and missed. That seems to preclude any claim the hospital was a legit military target, by the Iranians' own admission.