There's more than one idea, but it sounds like you understand it enough for this discussion. It sure sounds weird, but so's everything else about quantum physics; they've all turned out to be true so far though.
That's true. The parallel universe idea has some far-reaching implications. It has the bible thumpers really worried because it obviates the need for a creator. Since every possibility is played out somewhere there's no special "here".
So, the accusation of fear mongering was on target. It's all about selling those books. You're a joke, and not powerful at all. People like Ripskater listen to people like you because they don't feel like thinking for themselves. Nothing more.
TS, if you're really worried, it's these robots you should be concerned about, not some quantum computer that probably doesn't even work yet:
Incidentally, Boston Dynamics, the company making the robots, and D-Wave, are Google properties, iirc. They're the folks you should really be worried about.