You can argue that, but I can't believe that God would reveal himself to only humanity, giving us detailed knowledge of his character and plan and sending his Son to die for our sins only, but leave any hypothesized alien civilizations and their billions/trillions of other beings out in the cold so to speak. I would argue that goes against his character - he wouldn't do that to them, so therefore they don't exist.
It seems rather stretching it to deny the existence of any other intelligent beings based on a single use of the word "once" in the Bible.
Regardless, there will be many who will assume any aliens that visit us will in reality be demons from Hell. That will get ugly.