The reality is that there have been too many reliable observations, both by Mk 1 eyeball attached to trained observers and by instruments. If the USAF is reopening Project Blue Book, they believe there is something worth investigating.
The next question is "How do we communicate with them?" Are we still too primitive?
An alternate hypothesis may be that these are the equivalent of alien teenagers having a good time and showing off for their girlfriends.
The one thing we can be sure of is that we are not alone.
The paranoid hypothesis is that they are military scouts keeping an eye on us. I hope not.