Yes, we see only what we expect to see and write off the other stuff as noise. The example of the CD disc that contains nothing but 'noise' rather than communication.
I tend to think that any interstellar cultures near to us in development have learned not to mess with the natives. Not worth it and far too dangerous until they make the cut from their biological past and learn to quarantine primitive emotions.
The big jump could well be the transition to a fundamental energy form. Maybe 80% is advanced life appearing to us as dark energy. Chemical forms of life are so problematic.