I think the answer is pretty obvious: the alien civilization that's sending all the UFOs to Earth got wiped out in a massive cryptocurrency bubble, and the remaining survivors (who cashed out before the crash) altruistically decided to search the nearby stars for planets on which such an identical horror could one day arise. Sadly, their efforts fell foul of the fact that the most abundant element in the universe is not hydrogen but stupidity. The only question is: after our civilization similarly collapses due to a cryptocurrency meltdown, will a few surviving humans attempt a similar altruistic endeavor in turn?