I think his point is that, Trump provided the opportunity for these law professors to get their "dream job" (a seat on the supreme court, your name is in the history books for centuries). And yet, NONE of them took this up.
His point is that the groupthink at Harvard is so strong that people will actively demolish their dreams to stay within the group.
Thiel's insistence that Harvard law professors ought to have put [in this instance highly unlikely] personal advancement opportunities ahead of their actual beliefs about the fitness of a presidential candidate for office when deciding whether to make an endorsement says much about Thiel and little about groupthink at Harvard.
His point is that the groupthink at Harvard is so strong that people will actively demolish their dreams to stay within the group.