Israel has kidnapped tourists before. Vanunu is still trapped in Israel.
Where has Iran said that they intend to use nuclear weapons?
Mordechai Vanunu? His situation is quite a bit different than kidnapping a tourist that literally has done nothing to Iran except show up - or a freight ship traversing international waters. Vanunu leaked a ton of nuclear secrets about Israel and fled - ie, he was no tourist and your point makes no sense.
Whataboutism isn't a good reason to excuse Iran's extremely poor international behavior, nor condone their relentless threats against Israel and other nations (including the US). Nor does whataboutism excuse Iran's direct funding of terrorist groups that have killed Americans and other nationals alike.
With all these discussions, it's important to note the regime of Iran is not the people of Iran. The people are likely amazing and full of culture and history - the regime is oppressive and aggressive, which is not tolerated in modern times.
Nothing to do with the discussion here, just a random thought on the Vanunu matter.
Your other points rely on a rational actor... rational actors don't take freight ships hostage nor kidnap tourists.