A word on what science is
Science is -- at its core -- figuring out how to do something over and over, and get the same result. The how and why come later -- the important thing is that whatever we're observing, it is a repeatable observation. NASA has done this. It controlled as many variables as it could account for, ran the experiment, and is now going to publish the results. Maybe this device does generate thrust. Maybe it doesn't. Maybe mistakes were made. Maybe it's beyond our understanding. But definately: None of these things bother a true scientist. An experiment that confirms a theory is just as exciting (and important) as one that doesn't.
Unfortunately, there's the general public... and not being scientists, they don't understand this mindset. The average person has so little tolerance for running into unknowables that they invent fictions the moment one appears. I don't understand lightning therefore Thor is riding a chariot across the sky. NASA is right not to publish it, because it has already attracted the moths of mediocrity to the fire of enlightenment on this one. And when the excited dog of averageness wets itself on the carpet of knowledge, everyone's going to blame science for getting it all worked up... because that's what average people do. It's the reason we can't mention "cold fusion", "perpetual motion", or a few dozen other high profile things... things that we should still be researching; Or at least talking about and using as examples in our textbooks of how not to do experiments.
NASA doesn't want to release this because it is (rightly) worried that people will denegrate the organization, or the entire institution of science, when it turns out that the technology won't give them the flying car.