[Modernman]

Ever seen a robot round up a herd?

Just because we can't build robots that can round up cattle, doesn't mean that an advanced spacefaring civilization can't do better.

[Chris Talk]

Humans are much cheaper than robots. We do not build million-dollar robots to sew our garments together. We have it done in Honduras, Bangladesh, India, etc.

Humans are already here, do not have to shipped in, are self-replacing and easily disposable, don't really have to be repaired, require no electricity or feeding from the aliens, since they grow their own food. Can work in extremely hot and cold environments, live on almost nothing, much more durable than animals...