"Because ants are weak and worthless in the eyes of an earthling."
"You are correct. And that is why all of us will treat the lives of those earthlings similar to an ant. Why? because in our eyes, those earthlings are nothing more than weak and worthless."
'Except for the protagonist. That ant, although weak, has some worth.' Allen thought to himself.
After hearing Allen's analogy, Samantha dared not to question him anymore for three reasons.
One, Allen was right. Second, she was too weak to defend herself from Allen's power if Allen decided to kill her. Third, she already knows about the thoughts of an earthling because she was also an earthling, but not from this universe's planet earth.
Maybe it's because Samantha being an earthling gave her the courage to question Allen's morals. Samantha's origin as an earthling gave her the courage to at least prevent Allen and her classmates from treating earthlings as ants.