Because the UFO fanatics have been hyping it as it might have lent them some legitimacy.

Because it is an outstanding topic, coming from the highest government places. That is indeed interesting. No reason to bring your negative vibes in here.

Someone who is hoping to get a government contract to track UFOs is probably paying a lot of money for publicity.

It's really bizarre coming from such a (historically) no-nonsense organization

Maybe this is just so unavoidable as a marketing/PR strategy these days that even the military feels compelled to participate?

UFOs make for sexy, apolitical news. Perfect for hitting a broad audience, and the more sensational you are the longer you can keep them tuning in.