Well, yeah, dispassionately I understand why Iran wants a nuke, same reason anyone wants a nuke, power.
And dispassionately, I can understand why a drugged out gang member would want an AK-47. That doesn't mean I feel safe with him having one. And that doesn't mean I would sit back and let him get one in the name a fairness.
Again, think of the world as a Gang controlled south side Chicago housing project, and the police don't exist.
You know the bloods and the crips in the apartments next to you would break in, kill your family and take your valuables if they could. So, in that situation, is it not logical, you would want to big guns, while limiting access to big guns for people who threaten you?
And of course the bloods and crips will be thinking the same thing, they want the big guns, and you not to have the big guns, so its easier for them to force their will on you.
Yeah, disspassionatly everything you said makes sense... but I live in a world with consequences. Letting Iran get a nuke in the name of fairness might end up with many of my friends dead... so I'm not going to take a dispassionate view of the situation.
I want a nuke, I want my friends to have nukes, and I don't want bad guys to have nukes... it really is that simple.