Nuclear Iran

I'm not quite sure exactly what Iran is doing at the moment re the nuclear thing. If they are trying to make a nuclear weapon then I think that that is a very bad thing.
BUT...who the hell are we, the USA, France or anyone else to tell another country what they may or may not have??!!
We after all have these weapons.
I'm no fan of Iran and as I say I think Iran with an atom bomb (or whatever it is that they're called nowadays) is a bit of a potential disaster (a hell of a potential disaster actually), but who exactly elected the USA, France, GB, Russia, etc as the worlds judge jury and police.
There's something not quite right and very hypocritical about it all.