I haven't read any big news stories about this so it doesn't seen to have ruffle too many feathers, but regardless, it should be pretty obvious that he is not to subtly trying to remind us that the prime reason Iran and co are trying to build nukes is precisely because Israel has them.
If we want to make a lasting effort in the restricting the proliferation of nuclear weapons, this issue must be addressed.
Israel has no reason to have them. Its capabilities in all other areas of military affairs are a million mile ahead of the rest of the middle east, doubly confounded by even Russia's refusal to give them and even remotely modern weapons. Letting Israel keep them sends a message that the nuclear non-proliferation process can be circumvented just because we feel like it.
Compare Israel to North Korea, they live in close proximity to highly capable yet hostile neighbors like South Korea and Japan, and like Israel, the are not entirely certain that their biggest backer would assist in time to save the regime. They tried to build nukes as a deterrent.
Another example is South Africa. They actually built nukes, a few of them in fact. They had a justified fear of all those nut job run countries to the north, but the west was able to pressure them into disarming.
So now we come back to Israel. Who do they really have to fear? Lebanon is a mess and the political elite are trying to make the country democratic again despite the efforts by Hezbollah. Jordan is a friend, Egypt has the Sinai so they are happy, Saudi Arabia just wants money, Iraq will either be pacified or so self destructive that it wont bother anyone, Syria will probably get the Golan Heights back and will be happy.
This leaves Iran. For an Iranian army or even air force (which their best plane is 30 years old with no spare parts), they have to get through Syria, who would not accept the threat to sovereignty, or Iraq, or the Kurdish areas of Iraq, or Turkey, so the Iranian army can't even get there. Their air force is utter crap, you don't fight terrorist cells with nukes, so in a modern reality Iran does not possess that much a threat that could not be easily neutralize by diplomacy with its immediate neighbors.
From the Iranian perspective, Israel, China, Pakistan India, Russia, and the USA has nuclear in the region, all of whom don't really have a qualm about bombing a city or two just for the fun. what do you think Iran could do as a response?
In short, disarm Israel through economic and military support sanctions, bring old fies like Syria back to the west by some positive reinforcement, continue sacntions against Iran, basically, be firm but most importantly, be fair and not hypocritical.