"I think the Iranian leadership is composed of very rational people," Gantz told Haaretz. "But I agree that such a capability, in the hands of Islamic fundamentalists who at particular moments could make different calculations, is dangerous."
It could be that he is just trying to buy time for his gov't and the US to reach an agreement with Iran or for sanctions to play out. But if he truly believed as many in the US do that Iran is not rational he at least has a better feel for diplomacy than we do given his ability to blatantly lie. Given that I'm sure the general is smart and good at his job, I think it's safe to take him at his word. He knows that he has the far superior military to Iran and that his nuclear arsenal is a pretty effective deterrent if Iran were to get a bomb. We also have this comment by Israel's minister of intelligence about some infamous words from Ahmadenijad:
"They [Iranian leaders] all come basically ideologically, religiously with the statement that Israel is an unnatural creature, it will not survive," Meridor says. "They didn't say 'we'll wipe it out', you are right, but 'it will not survive, it is a cancerous tumour, it should be removed'. They repeatedly said 'Israel is not legitimate, it should not exist'."
It's funny how you aren't allowed to have a differing opinion about Israel in the US without being labeled anti-Semetic. But in Israel, people with a lot of power in their gov't are allowed to make statements like these. They seem to be aware that relations between Israel and the US with Iran are too heated and are trying to bring things back from the brink. It's comforting to know that at least some people in Israel are thinking critically and trying to let cooler heads prevail. Hopefully people in the US can follow their example and try to reach a constructive solution to the issues with Iran.