I think they are actually not allowed to pursue weapons and their complaint is that restrictions meant to prevent them from pursuing weapons are preventing them from pursuing legitimate research. Basically the argument is over how the IAEA is interpreting the treaty. I think the bottom line is that they what to at least keep the option of acquiring nuclear weapons open, to guarantee their own security. The catch is that many Israelis feel they can not guarantee their security if Iran has such weapons. Further complicated by the fact that the US has tough talked itself in to a corner on this issue. Finally we add good old fashion nationalistic pride and we get one big mess.