Why Iran should not have nukes

Why shouldn't Iran have nukes seems to be a question being asked by NGOs today? Is nuclear technology not a given right of every society?

Actually, that's not a hard question to answer and I pose a few questions in response.

Why should democratic societies be opposed to a theocratic jihadi supporting tyranny whose leaders ascribe to a doomsday ideology in order to bring about the return of a long dead prophet? Clearly, even with its huge oil reserves, the death loving muftis of Iran that comprise their leaders must only want nukes for peaceful purposes.
Surely, it has never crossed their minds to develop nuclear weapons and stick them on the end of their missiles, or hand them out to terrorist groups for plausible deniability?
By the way, although those missiles are now pointed at Israel, they are going to be pointed at Europe and the USA after the first launches.