The reason the powers that be believes he is immune to all disease is OBVIOUS. HE IS INHUMAN. A preprogrammged robotic automaton. Get it?

Remember HAL? He went bonkers. The powers that be was a prototype. A few glitches in the programming and he'll be fixed but who wants to work on him? No one that's who. Was I ROBOT the one about the robot who went bad and tried to get all the other robots to turn on humans? I think Will Smith was the lead in it. That's scary. Have machines turn on you en masse? Thank you for your reply Walt! :) This post was edited by RosieG at May 22, 2020 2:51 PM MDT

In the I, Robot movie, the "brain" that controlled the robots reached the logical conclusion that humans were a danger to themselves.
But it couldn't harm humans because of Asimov's 3 Laws of Robotics.  (or 4, if you include Law Zero)

1 - A robot may not injure a human being or, through inaction, allow a human being to come to harm.

2 - A robot must obey the orders given to it by human beings except where such orders would conflict with the First Law.

3 - A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.

Law Zero is: A robot may not harm humanity or, by inaction, allow humanity to come to harm.
But Law Zero is impossible for a robot to comply with, as this from Asimov's Foundation and Earth explains:

Trevize (person) frowned. "How do you decide what is injurious, or not injurious, to humanity as a whole?"

"Precisely, sir," said Daneel (robot). "In theory, the Zeroth Law was the answer to our problems. In practice, we could never decide. A human being is a concrete object. Injury to a person can be estimated and judged. Humanity is an abstraction."

So in the movie I, Robot the main computer was trying to follow the Law Zero, and protect humanity from itself.
The book is much more interesting (to me, anyway) as it's a collection of short stories regarding robots seemingly violating the Laws - but then shows the "logical" reasoning that explains why they really aren't.

Oh my goodness Walt! There you go again! EDUCATING me. Providing useful truthful information about something I touched ever so lightly upon never expecting such a great return on my investment! Wow! This is the first reply I've today and boy it's doozy. You know I think sometimes or maybe even often when I see something I think I'm getting all the meaning from it but then I find later on I didn't at all. Sometimes we think we KNOW and we really don't. Thank you for the detailed and very helpful information. So do you think one day robots will take over the world? Is AI limited so that humans will always be necessary for the existence of robots? I am going to ask that question. Happy Saturday Walt! :)

Please read WALT's reply to my question and then read yours. Which do YOU like best?

His is OK, but I like mine as well.