That's what happens when you only have a dataset
of one known planet that has life. All we know is based on our existence on Earth. In the vastness of the universe, there may well be countless worlds where "life as we don't know it" exists. Right now, all we have to go on is "life as we know it". That does tend to limit our perspective on where life, intelligent or not, could exist. As you pointed out, we simply don't know what lies out there. While I _believe_ the universe is teaming with life, I _know_ no such thing.