This has always been a problem with Facebook questions but it's much more pronounced now that SO is the official home of Facebook developer support. Looking at the newest questions list on facebook.stackoverflow.com, about half of the questions on the first page have been downvoted and given votes to close as off topic - most of which are totally on topic for folks who are doing Facebook development. It would seem that people are voting on these Facebook questions without having an understanding of what aspects of Facebook are developer-facing vs. user-facing.
Here are a few examples of things that were closed (several others have pending votes to close)... I'm not saying that these are all great questions but they are certainly the types of things that should be expected on the only official Facebook developer support channel.