Explain how it's unreasonable to not want a nuclear Iran.
I know you didn't direct this to me, but I don't think it's unreasonable to want a non nuclear Iran. The world would undoubtedly be safer if Iran, North Korea, Israel, and others didn’t possess nuclear weapons.
But most countries have already learned the clear lesson that without nukes they’re highly vulnerable to regime change at the hands of superior military powers. No matter what treaties are signed, this reality gives them a strong incentive to develop nuclear weapons in secret.
Furthermore, waging war to prevent a country from acquiring nukes is not only inefficient and deeply destabilizing to the entire region, it’s ultimately counterproductive. Neighbors have seen the precedent and feel even greater pressure to develop their own arsenals as a deterrent against future incursions.
We’ve already seen this exact pattern before. We hyped up "weapons of mass destruction" to justify invading Iraq, then dismantled the country and left it in ruins. Yet none of it made the world safer. Instead, there were serious unforeseen consequences. Most notably, Iran became significantly stronger once we removed Saddam Hussein as its natural counterweight.
The same thing will happen with our current actions against Iran. There will almost certainly be more unintended consequences. We just don’t know yet what form they’ll take.