>>213375775 (OP)
If I understand it correctly, it's not because humans are violent.
If we're accounting for Ridley's comment about "Christ being the last Engineer", and with Ridley's apparently Gnostic view of Christ (views he seems to share with Phillip K. Dick - the Bladerunner short story author) - the problem the Engineers have is man rejecting the natural order of life, rejecting death, rejecting struggle, becoming Nietzsche's "Last Men" and then having the gall to ask for eternal life: in the Engineer's view, Weyland was asking to become an undying center of decadence and moral decay.
"I come not to bring peace, but a sword" - Matthew 10:34
From this perspective, the Engineer doesn't kill David out of hatred, he attempts to kill David out of pity, because David is a robot that *can't* die, and experience life's intended cycle.
The ship is full of black goo that turns people into cock shaped monsters because it's a ship of death meant with love, for a species that had grown decadent and missed the point (in the Engineer's view) of life.
tl;dr: the problem is "Last Men" asking for more life.
And this is a really interesting reversal of Roy Batty asking for more life. Roy asks his creator for more life, and more struggle, more heroism, and successfully kills his creator when he can't get it. Roy has a lust for life, where Weyland is merely afraid of dying.
