If an alien race looked at us the way we look at dolphins, whales, or even primates -- we'd be damn lucky if they simply turned around and went home.
*edit: forgot "stop"
they're not trying to reach us and learn from us, and "swap ideas", as far as we know
and yet we still try to understand them and talk to them
if a dolphin was to one day utter: "hey guys, let's chat. let me tell you about my world, and you tell me about yours" - I think it would be all over the news, not glossed by like "pff.. stupid animal trying to think"
For certain terrifyingly-narrow definitions of "we".
Compare the number of researchers puzzling over sea mammal communication to the number of fishermen intentionally and unintentionally slaughtering them.
It would be as if aliens arrived and realized that Humans were sentient but hadn't yet puzzled out how to truly communicate with us. So they abduct a few of us and task a handful of them with trying to work it out.
In the meantime, the rest of them discover they have a taste for corn. So they dredge half of Iowa, shrugging their shoulders at the incidental death and destruction of any number of farms, communities and small towns. Then they dump the "by-catch" and leave.
Not to mention the havoc that would wreck on our economy and food supply and how many might starve in addition to those who would die directly. Not to mention the long-term damage their unsustainable harvest methods would wreck and the implications that would have on our own ability to survive. Not to mention any research stations that may or may not be causing massive cases of dementia/die-off of any number of humans.
The next year, when even more alien harvest ships return to do it all again, how much comfort are you going to find in the notion that the handful of them -- however earnestly -- are trying to learn how to communicate with us?