This blog post propounds a seemingly effective rebuttal to Stephen Hawking's aliens-as-conquistadors scenario. But its fundamental point apparently boils down to "Extraterrestrials advanced enough to accomplish space exploration (and overwhelm us with their technological superiority) won't bother because of the lack of a demonstrable ROI."
Along the route to making this point, the author manages to stand up some straw man arguments against such ideas as "we're the only intelligent life in the universe" and "we'd make good subjects for scientific study."
For me, Hawking's scenario delivers a Pascal's Wager-like persuasive payload against which this blogger's dismissiveness is ineffective. Consider Pascal's thought with the concept of intelligent extraterrestrial life in place of divinity:
If I saw no signs of a divinity, I would fix myself in denial. If I saw everywhere the marks of a Creator, I would repose peacefully in faith. But seeing too much to deny Him, and too little to assure me, I am in a pitiful state, and I would wish a hundred times that if a god sustains nature it would reveal Him without ambiguity Pensees
Would it not be a better wager for us in our "pitiful state" to accept a belief in the potential danger of advanced alien explorers than to assume that we can adequately calculate the economic disincentives to their putting Earth on their list of hostile takeover targets?
Why We'll Never Meet Aliens