I think this is Walter Jon Williams' "Dinosaurs" as the commenter above suggests
The story that caught my attention was about a mammalian species that recently had to destroy some "terraforming robots" that were making their worlds "safe for habitation" but there was a plot twist that the "aliens" who sent the terraforming robots were actually humans who had modified themselves to become disgusting, vapid beasts.
“Our terraforming Ships are very good at what they do,” Drill said.
“They are specialists. Our Shrikes, our Shrews, our Sharks— each is a
master of its element. But they lack intelligence. They are not
conscious entities, such as ourselves. They weren’t aware of your
civilization at all. They only saw you as food.”
“I believe,” said Cup, “we may avoid fixture misunderstandings, if
your Excellency would consent to inform us about your species. We have
suffered some confusion in regard to your distinction between
‘conscious’ and ‘unconscious’ entities. Could you please explain the
difference, as you understand it?” “A pleasure, your Excellency,”
Drill said. “Our species, unlike yours, is highly specialized. Once,
eight million years ago, we were like you— a small, nonspecialized
species type is very useful at a certain stage of evolution. But once
a species reaches a certain complexity in its social and technological
evolution, the need for specialists becomes too acute. Through both
deliberate genetic manipulations and natural evolution, humanity
turned away from a generalist species, toward highly specialized
specialized forms adapted to particular functions and environments.
The species in the story that was in the process of being colonized ends up voting for a politician to go to war against humanity instead of turning over the locations of their other colonies, but the previous leader comes back to Earth with the "human" who was sent to negotiate after the negotiations fail, resigned to the fate of her species.
Vang, now simply General Vang, arrived at the field. His followers
danced intoxicated circles around him as he spoke, howling their
responses to his words. “Triumph! United will!” they cried. “The
humans can be beaten! Treachery avenged! Dictate the peace from a
position of strength! We smell the location of their planets!” The
Shars’ weird cackling laughter followed him from point to point. The
laughing and crying went on well into the night. In the morning the
announcement came that the coalition had fallen. Vang was now
President-General.
“How long,” she asked, “do you think we have?” “A few years. Ten at
the most.” “Our species will be dead.” “Yes. Exterminated. Our
military are very good at their jobs.” “You will have killed us,” Gram
said, “destroyed the culture that we have built for thousands of
years, and you won’t even give it any thought. Your species doesn’t
think about what it does any more. It just acts, like a single-celled
animal, engulfing everything it can reach. You say that you are a
conscious species, but that isn’t true. Your every action is...
instinct. Or reflex.”
The story has been edited in many places
https://www.isfdb.org/cgi-bin/title.cgi?41483 - some of which like the
"The Furthest Horizon: SF Adventures to the Far Future" (2002) might well have been picked by a professor in 2005.
