"the theory that there aren't any which is supported by a huge volume of evidence from SETI."
You MUST be joking. Our SETI has yet to even scratch the surface. Proof is the simple fact that our existing SETI system would not be able to detect a duplicate of the Earth itself at the distance of the nearest star, despite the massive transmission of radio signals from Earth.
In short, looking under one tiny stone does not constitute a search.