Facebook had submitted a motion to dismiss the lawsuit. A motion to dismiss means they assume that every fact alleged by the FTC is true. You perform a motion to dismiss to say "even if everything they said is true, it still isn't even possible for them to win the lawsuit." The judge said, essentially, that if every fact the FTC alleges is true, then it is at least feasible that the FTC could have a successful lawsuit. There are two key things that this go ahead does NOT do:
1. It does not look at whether even a single alleged fact by the FTC is true
2. It does not mean that the FTC suit would be successful even if every fact is successfully proven