The irrationality of [many] extraterrestrial visitations via UFOs
This schema of the Universe and where we are in it shows that advanced civilizations elsewhere would never, even accidentally, stumble upon Earth and engage in returning, multiple visitations.
To persist in the idea that extraterrestrials (an alien culture) have visited and are visiting this non-descript planet is irrational to the point of insanity.
One might argue that an advanced civilization close-by (on a moon in our solar system or from a planetary system a few light years away in our galaxy) might account for UFOs but, in the numbers indicated by the raft of UFO sightings/reports, that possibility is also a mental/logical stretch.
Ufologists have got to come up with another scenario to explain the UFO phenomenon. Otherwise they (ufologists and UFO buffs) must be deemed to be mentally deficient or mad.