Fortunately plenty of people are sane enough to do a reality check before they believe in anything.
The trouble is that space aliens has become a religion, complete with prophets, contactees, sacred sites, artworks and all the other paraphernalia typical of a religion. Everything except peer reviewed, verifiable evidence.
There are as many grains of sand on Earth as there are stars in the universe. But not one of those grains of sand support life.
In any case, we can only ever see a tiny fraction of a percent of stars in the universe, let alone their planets. All stars are in galaxies, and of all the billions of galaxies in the universe, we can only resolve the stars in a handful of nearby galaxies. Hence even if there was “life” somewhere in the vast remoteness of space, we could never detect it. So what point is there making a religion out of it? Why does it even matter. There are far more important things to spend your precious time on.