Yes. The most charitable interpretation is that people have forgotten the lessons of the 1900s and think that a replay of Herbert Hoover is a good idea.

Last time it took a few decades and destroying countless lives to fix. Hopefully the cost is lower this time.

Yes, I understand what you're saying, it's not a complicated position.
Your position is that national reputation matters more than anything else. And most pointedly, the national reputation of your allies matters more than any other argument.

What I'm saying is, is that the actions the US, or any other nation, took before the people currently running things were even born have no bearing on current events. Nations aren't people, and they don't possess a national character that you can use to try to predict their behavior or judge them.

Would the world be justified in concluding that it's only a matter of time before Germany does some more genocide? Before Japan unleashes atrocities across Asia?

If you're getting down to it, the US can't control other nations, beyond stick and carrot means. And the US has the same right to try to keep Iran from getting nukes as Iran does in trying to get them. Because again, nations aren't people. They don't have rights, they have capabilities.

And all of that's irrelevant! Because the question is, is Israel justified in attacking Iran? The perception of hypocrisy in US foreign policy isn't relevant to that question.

No, what I don't understand is what relevance that has to this situation. The US using nukes on Japan 80 years ago doesn't make Iran making nukes justified. It doesn't validate Iran not having nukes. It neither strengthens nor weakens Israeli claims of an Iranian weapons program, and it doesn't make a preemptive strike to purportedly disable them just or unjust.

It seems like you're arguing that the US nuked Japan and therefore Iran, a signatory to the nuclear nonproliferation treaty, is allowed to have nukes. Israel is falsely characterizing their civilian energy program, and we know this because of their backing by the US.
It's just a non-sequitor, particularly when there's relevant reasons why US involvement complicated matters. .

What does that even mean? How is what a nation did generations ago relevant to two different nations in a totally different scenario?

The USs actions in world war two are an odd thing to bring up in this context. It was a radically different set of circumstances, 80 years ago, and none of the people involved are alive anymore.
It's entirely irrelevant.

May as well point out that the US was the driver for the creation of those watchdog groups and is a leading force in nuclear disarmament. It's just as relevant to if Iran has a nuclear weapons program or Israels justification for attacking.

Iranian opposition to US strategic interests in the region giving the US a strong motivation to let anything that makes them weaker happen is a perfectly good thing to mention.