Iran - doubts, hypocrisy and bullying

I have been trying to get my head around Iran and my opinions on it.
Yet again, they have decided not to comply with the UN's requirement that it stop enriching uranium. They seem to thrive on this kind of brinkmanship.
And you can see their point, quite frankly. They are a proud nation, and do not take kindly to interference in their internal affairs, especially from the overbearing and holier-than-thou USA, the "Great Satan" as the phrase went in the Ayatollah days.
Under the Nuclear Non-Proliferation Treaty (NPT), Iran has the right to pursue a nuclear power programme under IAEA supervision, and it has said that it will not use the technology for weapons manufacture. Which ought to be the end of it, one would have thought.
However, the problem arises because the UN (and the US in particular) don't believe them. Nyah nyanee nyah nyah... Again, there is some justification for this based on Iran's dubious past performance, but international policy can't be built around sneaking suspicions of duplicity.
No-one trusts the US any more (remember those Iraqi weapons of mass destruction?), but no-one is clamouring for their complete nuclear disarmament, despite their obligations to pursue this under the NPT. Well, actually, many of us are calling for just that, but the UN is not, and there is clearly some measure of hypocrisy there.
Israel, just as trigger-happy and unreliable as Iran, has nuclear weapons, and is not a party to the NPT. Ditto: India, Pakistan and North Korea (maybe). The USA is, of course, the only country to have ever used the damned things.
Personally, I would like to see nuclear power deep-sixed, not just nuclear weapons, so it is with distinct mixed feelings that I have to conclude that the UN is being hypocritical, the US tyrannical and bullying, and that Iran has a reasonable case to be left alone to develop its own nuclear power programme.
Iran's intransigence and it's rather puerile approach to many aspects of international relations is realistically unlikely to change much, and one could wish for more common sense and good old-fashioned reasonableness from Mr. Ahmadinejad. But, having observed recent events in Afghanistan and Iraq, you can understand his concern and distrust.