The main reason why they are updating their guidelines is that there is a negative stigma within the military about reporting UFOs. Essentially if the flying object does not have a tail number (or a tail for that matter), military personnel tend to remain silent. The Navy is trying to remove the negative stigma that goes along with reporting UFOs.
Despite the stigma, a number of well respected officers have reported flying objects that move in very advanced ways and there is speculation that there would be more reports if there was an official policy for how to report a UFO. You can read the full Politico article here.