It's interesting they do not believe in God without evidence, but the non-believers will believe in aliens without evidence. Just because of vastness of space. That could be the reason for God, too. He's living out there somewhere.
Failure to believe in a God is mostly a failure of education in pure Philosophy.
Philosophy contains many classic proofs of God.
Aristotle was the first, and his proof was the Prime Mover.
Aquinas came along and besides that one gave at least 4 more.
Descartes came along and gave at least 1 more.
Once you confirm the existence of a God then the next step is simply to pick and choose from among the plethora of world religions of which hopefully one is appealing.
As for aliens, I am sure they are out there too -- just too far away to touch us here -- even as we ourselves are too far away to touch them.
All in all the Earthlings and Aliens are presently safe from each other.
Someday we will make radio contact, but even then they will still be too far away -- light years.