However it has to do more with the question of complexity. Humans are very complex.
Now, intelligent design doesn't have to be by "God"; it's very possible that "extra terrestrial" intelligence could've either sparked or helped the development of humanity. Do you find that idea absurd?
I find the argument- we're very complex. Something we've never observed before (ET's, god, pink unicorns) must have done it a very poor argument, especially considering that there's no evidence for aliens, God, or Pink Unicorns.