It means that professors would rather work on their research than help you with your problem set. It means your professors would rather be surfing the web looking at nudie pix than lecturing undergrads. In their eyes, an undergrad can never achieve anything worth mentioning and thus they're a waste of time. It may appear as if I'm casting Yale's faculty as demonic spawn. This is far from the truth.
Professors are human beings and are nice people.
It's just that the profs at Yale have important research to accomplish, and the onerous task of lecturing is seen as a minor speedbump on the road to tenure and fame. Depending upon your attitude, the Golden Rule can be used to great advantage by a student. Much of this document explains exactly how. Before I go on, people will surely take issue with the Golden Rule. Yes, this happens, though rarely.