User blog comment:The Milkman/No Love For Leviathan?/@comment-4947725-20120917050702/@comment-24174486-20120917175818

"If Leviathans can knock out Reapers, the WHAT THE HELL have they been doing with their time?"

They've been hiding from the Reapers. They were driven to near-extinction, and there are thousands of Reapers. While they can deal with a single Reaper, it's unlikely that they would stand a chance if the entire Reaper fleet discovered them.

Another "I didn't bother to listen to/acknowledge the dialogue" "plot hole".