"Terrorism" has as its goal the specific targeting of innocents as a means of creating fear and repugnance in order to effect a political agenda.
Israel takes the stance that these individuals are NOT innocents, but actively engaged in a war against Israel and therefore legitimate military targets. Israel is not seeking to inculcate fear or generate repugnance on the part of Iran. It is trying to kill key personnel. In their eyes, it is little different from a sniper singling out an officer on the battlefield.
Please note, I am ONLY disputing your use of the term terrorism, which I believe gets too watered down. I am setting aside the morality or immorality of Israel's alleged actions in this as a separate question.
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