They knew each for, what, a couple months? I think she wasn't terribly broken up about him leaving because she feels like you do. She was disappointed, but knew if he was gone that easily, they did not have enough at that point to compromise areas of their lives they were sure about. And staying in touch with an ex closes you off to potential new possibilities, so I think it was right that they cut ties.
I think we are saying the same thing. And believe the same way, actually.