He is a fool. (Potentially career-ending statement from me there, given that he's my boss, and politicians tend not to cope well with challenge).
If your plan requires a million people to move in 24 hours, and you know that they can't, then you need a new plan.
Even if the 24 hours proves to be a somewhat elastic concept, the negative effects of a million people trying to move in 24 hours are deeply problematic from a humanitarian and moral - and I would argue, political in the medium/long term - standpoint.
I think the Israelis have really fucked up with this - and Shapps could have skirted the issue by simply saying (and resaying) that we are in constant contact with the Israelis to both support them, and to offer our candid advice as a friend. That might not have pleased the interviewer (I listened to it), but it would have avoided answering the direct question and allowed anyone listening to hear what they want to hear - we are supporting the Israelis, but we are not saying that this is a good idea.