Great scene... Complete with clandestine organization symbolism of checkerboard floors and columns flanking doorways. The Big Lebowski is an alien! The militant, hierarchical aliens hate rebellious humans who won't comply and be slaves, like the Dude. The sunglasses are clearly a reference to They Live! He puts them on when he's heard enough, then turns his back on TBL and walks away, with a plan to take back what was ruined by simply taking it. Just what we should all do.

Everyone should become a Dudist, right now.