"Oh look, another “do aliens exist” thread devolved into another religious debate. Surprise, surprise."

Yes. It comes from the unfortunate thinking of many, which says, "I don't understand this, therefore it was God!" This thinking ignores all of the ways that science has whittled away the old religious beliefs of the past. You could be excommunicated and even sentenced to death at one time for teaching that the Earth revolved around the sun. Everybody knew that the entire universe revolved around the earth! Well, they don't now. This, "It must be God," reasoning has no place in the 21st century. My humble opnion, anyway.
This is all something that we simply don't know the answers to, right now. One day, we will. And the answer isn't going to be any angels or gods.

"From our orbital vantage point, we observe an earth without borders, full of peace, beauty and magnificence, and we pray that humanity as a whole can imagine a borderless world as we see it, and strive to live as one in peace."
Astronaut William C. McCool RIP, January 29, 2003 - Space Shuttle Columbia