This speech was given to Princeton undergraduates -- 1150 of the most fortunate and well supported people in the world. He's urging them to be self aware of their immense good fortune, and to be generous and grateful rather than selfish and envious.
Princeton is the epitome of a capitalistic school. Very few students will become socialists. Having more Rockefellers and Carnegies (who have both given to the university) is not a bad thing for this world.