Should they though? In the current climate that seems risky, if your donation to the university wasn't used for education but instead spent building infrastructure on Africa then some folks would likely decry that investment as being self-serving (trying to build good PR to cover up some perceived bad event that recently happened), or it might be decried as being injust (sure, they invested into that village, but the neighboring village was so much worse off), or it might be controversial (did you know that the village you gave money to was the home of the mother of the former dictator that raised a child army over here)... or it might just be decried as being wasteful (if the university has so much money to spare why should I donate to it - they're just lighting money on fire trying to fight causes that have no relation to education).

I think there isn't an easy answer to this question and just letting the ball of cash grow bigger honestly might be the only "safe" decision we've left open to universities... that said pumping it into mutual funds managed by the president's husband or giving steep raises to administrators also looks terrible from the outside.