You have a point!!!!!!
There is wisdom in your acknowledgment of our relative ignorance.
EVERYBODY believes in extraterrestrial beings!
Most believe in God or other beings/deities not of this world. And, yes, the most widely read document (the Bible) on this subject does actually refer to ET vehicles.
Some believe in the gods Time and Chance. That we are here by accident and are molded by eons. And The Book of Chance (1:1) tells us that life exists elsewhere.
Between those with faith in God and those with confidence in Darwinism, I don’t know a single soul who believes we are the only life in the universe.