Most people don't see the obsession with ufos for what it has become subliminally for many: a form of secular or scientific mysticism.
For many agnostics and atheists, the plausibility of alien life visiting us conveniently fills the yearning for some higher power
while also filling in the gaps that science has no persuasive explanation for, such as how did life form here.
Given the astronomical odds against life forming in some primordial soup even the scientific establishment has begun to embrace the idea of panspermia, microbial life coming here on comets or asteroids. Aliens are also a convenient substitute for God as their imagined technology would make them godlike in terms of their intelligence and abilities. Once they reveal themselves we might gain access to free, limitless energy, the cure for every disease, and universal peace under their guidance.
That is some of the thinking of the UFO cult.
Lastly, belief in such benevolent overlords frees the individual from all those pesky rules inherited from the Abrahamic religions.
The idea of sin and guilt can be jettisoned completely since those religions would be totally discredited.