Israel's aren't illegal. They didn't sign the nNPT (nuclear non-proliferation treaty). The idea of which is that the 5 nuclear powers are supposed to work towards total disarmament and trade civilian nuclear tech with signatories - but signatories aren't allowed to develop nuclear weapons tech. Everyone is subject to inspection and signatories aren't allowed to trade civilian tech with non-signatories.
Iran and North Korea did sign, then illegally developed secret nuclear weapons tech while signatories. North Korea then pulled out.
This of course raises trust issues. If you promise not to develop nukes, then get caught doing it in secret, people tend not to trust you when you say you don't intend to use them. Obviously it would be better if Israel didn't have the things either (it would be best if nobody did) - but they didn't lie to anybody about it - or break any treaty commitments they'd signed up to.
Biting the hand that feeds IT
