Facebook is now explaining how the Graph Search will work for younger users, i.e. teens. Teens get different set of Facebook privacy defaults and the same is true for Graph Search.
For one, teens can't share anything publicly, everything is restricted to "friends of friends" as the most liberal privacy setting.
This means nothing will show up for public searches. In fact, no identifiable data about anyone younger than 17 years old will show up in searches for anyone outside of the Friends list and Friends of Friends who are also under 17 years old.
Facebook also reiterated some safety tips like reviewing your activity log to see what you are sharing as well as the About Me tab to see what info is available to others.
Facebook is still rolling out Graph Search, but it's doing it very slowly and deliberately, understandably for such a sensitive feature.
People get upset by anything that Facebook does, the Graph Search actually has some privacy implications, so Facebook is doing the first move and keeping people informed, as much as possible, before another "scandal" breaks out.