I think the MacArthur Foundation is old Rockefeller money, so PC it is.
Oh, the funding initially came from the extremely wealthy MacArthurs. Rockefellers have their own foundation(s).
BUT lefties are attracted to foundations just as they are to academia and the media. So, most people who work for foundations, and/or serve as directors, tend to be of the left.
I think it’s possible the MacArthurs were somewhat to the left themselves, maybe old timey liberals. Both began life very poor, so may have tended to liberal social programs. Not sure.