This is one reason why I tend to doubt whether, in many cases, diplomacy is effective.
Look, if Iran wanted a weapon, any weapon, that couldn't affect anyone outside their own boundaries, then so be it. Go after it! But, nuclear weapons can affect anyone OUTSIDE those boundaries.
The basic fact in my mind is that I simply do not trust the leadership there., nor their agenda(s). And, it has nothing to do with Islam per se, only their apparent veracity in the application of Islam.