If aliens are in fact coming here, why would they
travel hundreds even thousands of light years
Why do you assume that they travel hundreds or thousands of light years? They could be be teleporting. They could be time traveling. They might occupy extradimensional space within our own solar system.
Next, even if they do travel hundreds or thousands of light years, why do you assume that this is not trivial for them just because it's impractical for us? You as a human can easily book a flight thousands of miles across oceans. It's not a big deal. But it would appear to be a big deal if you were a housecat. Or a gnat. Or any other species on this planet without access to the technology humans have.
and not do anything?
Why assume they don't anything solely because you haven't seen the sort of activity that you would expect humans to perform for other humans? Try to imagine a tagged whale trying to explain to other whales his "abduction" experience?
logic says if they're willing to travel that far through space they
would try to contact the planet as a whole
Whose logic? And why?
Humans routinely travel hundreds and thousands of miles in boats, dive the seas in scuba gear and submarines...and yet I don't see anyone trying to make wide and formal contact with plankton or mudcrabs.
And...those few and rare humans who do try to communicate with ocean life, like people who experiment with dolphin communication, generally only contact a few creatures. They don't go looking for dolphin councils and establish full time embassys.
[edit on 9-11-2008 by LordBucket]

