Supplementing other replies regarding the centrifuges (e.g. no sole use for nuclear enrichment, only enrichment in less steps/faster), one ignored point is that Iran's centrifuges are not an Iranian but an imported Pakistani design. You could argue that the Pakistanis did indeed use their centrifuges to produce bomb-grade uranium. However, given the context that the USA prevented Iran from gaining nuclear technology it was entitled to under the NNPT with diplomatic pressure, getting even China to renege on contracts, the "you get them where you can" argument holds.

Others also addressed the 'acceptable' and 'snuffed' offer from the Russians, and elsewhere I addressed the unreported part of Iranian offers and EU-3+USA refusals.

I add a further point. You acknowledged that the beryllium issue was false. You probably also remember the highly-enriched particles in Iranian centrifuges touted as absolute proof, which turned out to have been contamination from the Pakistani manufacturer. A third example is when the USA touted photos of Iranian nuclear facilities including Arak, claiming they are held secret - despite the facts that (a) under the NPTP, new facilities have to be reported six months before they come on-line - in Arak's case, that would be in late 2013 -, (b) the facilities were, in fact, already known by then, only not visited, (c) Iran has invited the IAEA to inspect those facilities, which then didn't yet happen.

Now, do you see a pattern? One reminding of 2002/3?

We want to ban nuclear arms, not promote it.

Indeed. And the NNPT explicitely involves the promise from existing powers to dismantle their arsenal. But they refuse to do so, what's more they refuse to give up on the first-strike option, in fact issue threats to use their nukes (USA, France), what's more one of them (the USA) wants to build a missile defense system that would strategically weaken rival existing nuclear powers (by reducing their return strike capacity). I don't know about you, but I cannot convince myself that this talk is only empty rhetoric, I do see a spectre of nuclear war. In this context, one possible target gaining deterrence may reduce the threat of a nuclear war.

This is not a promotion of nukes, quite the contrary. This is purely a counter-argument to the threat argument, and points to problems I see as more much serious on the way to ban nukes.

_{*Lunatic*, n.
One whose delusions are out of fashion.}