It is a creepy app that exposes folks publicly available data, but I think the idea that it is designed to help stalkers prey on girls is a stretch.
In fact, I think it's a good thing that such an app exists. The bad thing is people not knowing what they share, and that needs to be fixed by Facebook/Google, or through laws. The situation is not that much different from exposing a security hole in order to get it fixed. Besides, some people may actually want their data to be available like this, so once it's strictly opt-in, there's nothing wrong with the app.