When nuclear states seek to reduce their arsenals towards the goal of complete nuclear disarmament because no state can afford them, why is it that Iran keeps its one and spreads offensive rhetoric?

They have civilian power supplied by a neighbouring state (Russia) under international auspices and checks at the Russian end.

Therefore could Iran also put its missiles out of use at the same time as Israel and Pakistan / India / China/ USA/ UK/ France as that way there'd be no need for weapons and no risks of aftershocks if the Guardian report is accurate and there's a bomb being developed near the civilian plant at Natanz (reported repeatedly as the main site in the UK press over the past ten years).

Then saved resources could be used on managed debt default and the Holy sites in the Middle East don't get bombed out of existence by any Iranian reprisals.