At least religious people have an excuse because their belief comes from a place of suffering, no one who thinks these sci-fi fantasy concepts are real is suffering, these beliefs come from a place of extreme comfort, nobody who believes in aliens is from the global south, how many times do liars need to stand in front of governments and say “aliens are real” for there to be some kind of explicit denouncement from atheists for these absolutely non-atheistic beliefs that get a pass because they are sci-fi. PURGE THE NERDS!
We understand how life came to be on Earth, and that the mechanics of such are mundane enough to reasonably occur elsewhere in the universe, and that's only with the form of life we're familiar with and ruling out any other possible forms of life that might use entirely different chemical processes than we do.
In a functionally infinite universe, the odds that those same circumstances repeat somewhere is guaranteed. Whether that life is intelligent or not is anyone's guess, but it exists.