What are you talking about "facility"? The human, named Mohsen Fakhrizadeh, was a military target, since he was the head of the nuclear weapons program in Iran.
I'm unclear what the relevance of "many civilians around". Do you imagine military targets are always isolated with never any civilians near them?
> I am doubtful that Iranian agents doing these same actions to scientists in the US or Israel on the street would be considered a legitimate military action and not terrorism.
A scientist in the US or Israel working on developing a nuclear weapon would be a military target. Why does this surprise you?
There's a reason you don't know the names of any scientists in the US or Israel working on nuclear weapons: They would instantly become targets.
Do you imagine war is some kind of game where everyone is like "it's my turn now", and there's a referee?
I am doubtful that Iranian agents doing these same actions to scientists in the US or Israel on the street would be considered a legitimate military action and not terrorism.