It's a gamble to come to America to get educated (cost, cultural adjustment, visa issues), and I think that we should show preference to those students who have made that extra effort to live and study in America over other people.
I just answered this elsewhere as well. This reasoning would make sense if that's what they said. But the explicit reason for the changes is to get more "skilled" workers in. Then, it should not matter if the degree was from US or Europe or China. I would have accepted this reason if they had separate weightage for "How long the person spent time in the US". This particular formulation puts a graduate from Europe at a disadvantage, for example.
