"Guarantees" how? I mean, if you're writing your own AI, and you're assuming that it'll be hostile no matter what you do, then that is indeed evidence that you'll end up making a (non-anthropomorphically) hostile AI or fail to make an AI at all; and if you're writing an AI that you expect to be hostile, maybe you should just not write it. But a Friendly AI should still be Friendly even if the majority of people in the world expect it to be hostile.
People are friendly to dogs they assume to be friendly, and hostile to dogs they expect to be hostile.
Likewise if an AI has self-preservation as a higher value than the preservation of other life, it will eradicate other life that it'll expect to be hostile to it.
In short by being too scared of AI, we're increasing the risk that some kinds of AI (ones that value their own existence more than human life) will destroy us preemptively.
Here is another example of an outsider perspective on risks from AI. I think such examples can serve as a way to fathom the inferential distance between the SIAI and its target audience as to consequently fine tune their material and general approach.
via sentientdevelopments.com
This shows again that people are generally aware of potential risks but either do not take them seriously or don't see why risks from AI are the rule rather than an exception. So rather than making people aware that there are risks you have to tell them what are the risks.