Quote by @Morphius:

"Why do the bad ETs need us for a slave race? Courtney says to expand out into the galaxy. Wouldn't it be easier to 3d print robots. You don't have to feed them, etc. I don't buy that narrative. Technically, you could eliminate them and just create robotic engineered beings."

You assume that humans will stay the same and fight in human form. But that's not the big picture.

If you look at Earth as a prison planet, you can also see it as a factory. But what's the main product? Human soldiers? No.

The main product of Earth is ISBEs with a narrow and authoritarian belief system. Traumatized people who follow orders without questioning them. So, how do we get there?

See, the biological human body was especially chosen because of his weakness (when compared to other alien species). That weakness affects the mind. If you make humans grow up in a hostile environment, their bodily weakness contributes to the weakness of the mind. It's a form of brainwashing. The bad ETs need weak minds, because strong minds would not only resist the drill, they would also resist authority as a concept.

When a human soldier is "ripe", you can pull his soul out of the human body and put it into a synthetic supersoldier body.

Why do you think they make the Avatar movies?