It's not just the donors. Theres an Ivy League premium because a school's name opens doors for their graduates in the corporate job market(and as future business leaders) and a majority of US based corporations are implicitly pro-Israel. There has been some fairly vocal business leaders calling for an embargo on hiring graduates from schools seen as anti-Semitic.
Like it or not, but that's how it works - the Ivy league schools get their reputation for placing their graduates in successful future career paths and it's a reputation they need to protect for self preservation. And as for corporations, they want to hire managers and decision makers who keep quiet about controversial topics, because saying the wrong thing ultimately affects business.
Case in point - the president of the NYU Student Bar Association lost a job offer at a
after she issued a statement supporting Palestine immediately after the Hamas attacks on Israel. This was followed by
for students that made public statements blaming Israel for the attacks.