Comment don't hide under the bed (Score 1) 1015
The kind of fear of aliens he's proffering is a mere extension of our fear of our own mutual aggression because of our being primitive enough to have such a concept called "war," and the fact that we're not even smart enough to live in harmony with and hence sustainably in our own environment, and we didn't need to hear it from Stephen Hawking for those particular two synapses to fire. His ideas aren't new or fresh; we just have a tendency of treating them as something profound because they happen to come from Stephen Hawking. Think Independency Day, War of the Worlds, Aliens, Predator, Earth: Final Conflict, Stargate SG-1, etc. etc. going back decades. Just because he's good at math and cosmological speculation (*speculation*, no less -- he's not an oracle) doesn't mean that he has any special insight on this topic. He's just having fun with his authoritative status..
If they have bad intentions we won't be able to stop them. If they have good intentions and let us know it and we don't believe them, running away won't be an option (unless they leave voluntarily just because of the distrustful atmosphere). In fact if they have good intentions and they're smart (which they would be), such a fear of them would probably delay any ambition of theirs to publicly contact us. The ideas he's spreading are merely the planetary-level analogue to xenophobia or agoraphobia, or as the OP said, "hiding under our collective bed" with respect to the greater universe -- as if we're not a worried and anxious enough species already.
On the topic of the aliens themselves, though.. considering how new our technological development is, and how long species tend to last, and the mere hypothetical fact of their being able to reach vast distances to get to us, we're perfectly willing to admit that they may be millions of years "older" than we, technologically speaking. But we don't seem to fathom that being around for millions of years would likely mean growing in all imaginable dimensions, not just technological -- spiritual, emotional, psychological, cultural, universal understanding/awareness, etc. Even here on Earth some humans are vastly more advanced than others (think Gandhi, Sai Baba, the Dalai Lama, and so on), and they don't even have the advantage of a sane culture or a million years of cultural evolution. Just imagine how graceful the aliens must be -- in fact that's probably the *only* reason they haven't made a public announcement of their presence: they're probably well aware of us and smart enough to either a) follow something loosely like the "Prime Directive" (I say "loosely" because they wouldn't be dense enough to treat it as an absolute even at the expense of common sense or compassion), and/or b) they don't want to cause the mass panic or even just general anxiety that would result from such an exposure, or if nothing else to impose themselves where they might not feel particularly invited by the collective mentality. My belief is that, though there are always exceptions, in general the other species in the universe are at best like "big brothers" (not Orwellian), and at worse something like an average neighbor -- not particularly malicious, and likely willing to lend a helping hand if they happen to come across such a necessity.