Hmm. Good question.
I'll go line by line here;
To Examine, Enslave, or Devour Us: They could probably do this without our knowledge. Maybe they're in cahoots with the IRS.
For our Water, Air, Chemicals, &/or Minerals: Not likely. If they can make it here, they really wouldn't need to ask permission and it would just happen before we knew it.
In Search of other Intelligent Life: HAHAHAHAHAHAHAHAHAHAHAHA *breath* HAHAHAHAHAHAHAHAHAHAHAHA (fat chance, aliens)
To Share their Technology & Advanced Knowledge: Even a cursory glance at our self-destructive nature would inform them to how bad of an idea that would be.
To Unite Us with Other Worlds: This seems lovely. Maybe.
To Destroy Us for the Safety of the Rest of the Universe: Frightening how much sense this makes. Probably good policy on their part.
To Harness the Power of our Sun: Stars like ours aren't that hard to find.
The optimist in me is going for Unite.