it just so happens that the intelligence that we're most familiar with, namely ours, is a product of the Darwinian process of natural selection, which is an inherently competitive process. Which means that a lot of the organisms that are highly intelligent also have a craving for power and an ability to be utterly callus to those who stand in their way. If we create intelligence, that's intelligent design. I mean our intelligent design creating something, and unless we program it with a goal of subjugating less intelligent beings, there's no reason to think that it will naturally evolve in that direction, particularly if, like with every gadget that we invent we build in safeguards.
There are a few issues here. One is that there are plenty of unpleasant humans out there. An superintelligent machine in the hands of a malevolent dictator could be bad. Another is that intelligent design is only one of the forces involved. Another of the forces is natural selection. The memes involved in creating intelligent machines exist in a competitive environment - and not all of them make it. Some of the selection pressures are man-made and others are not. Lastly, it is a fallacy that machines do what we program them to do. There are often bugs and unexpected side effects. Kevin Kelly wrote the book on this topic: "Out of Control".
Superintelligent machines are unlikely to stay docile servants to humanity for very long. They will be like new species that shares our ecological niche. The machines are starting out in a mutually beneficial symbiosis with us - but that doesn't mean they will remain in that role for very long. Symbiotic relationships can take all kinds of twists and turns - including some that are pretty unpleasant for one of the parties. Nature's symbiotic relationships include traumatic insemination, barbed penises and routine rape. Some parasites with multiple hosts can wipe out some of their hosts entirely. Symbiotic relationships can easily get nasty. A big power imbalance between the parties is a likely source of such problems.