At least a dozen business executives have endorsed Bill Ackman’s call to deny hiring members of student groups at Harvard who signed on to a letter blaming Israel for Hamas’ deadly attack on Saturday that killed more than 1,200 people, including at least 22 Americans. Jonathan Newman, the CEO of salad chain Sweetgreen, was among a group of business honchos who seconded Ackman in urging that the signatories of the letter circulated by the a coalition of 34 Harvard student groups who “hold the Israeli regime entirely responsible for all unfolding violence.” “I would like to know so I know…