But, anyway, they all came back to their senses, started
shooting at each other and developed many wonderful
weapon systems.

And why is that?

Rhetorical question 1:

Is there some defect in human beings which causes them to destroy that which
they covet?

Rhetorical question 2:

Do ya suppose the aliens know what the problem is?

Rhetorical question 3:

Do ya suppose the aliens have genetically 'tampered' with some human beings?

Rhetorical question 4:

Do ya think they've suceeded in 'breeding' out human kinds self destructive
biology?