That's not capitalism by any definition.
That's extortion and it was a well known practice thousands of years before we invented (or at least understood) capitalism.
I'd argue capitalism is not even an ideology, it's just a simple understanding of comparative value and how to go beyond zero-sum economics.
In the example of "give me what I want or I'll shoot you", you could argue that "X prevents Y from being shot" and "Y gives X what he wants" is a benefit for both sides, but that ignores the first part, "X puts Y in a position where he is going to be shot" is not mutually beneficial, so the salient part of the example (the threat) is not actually an example of mutually beneficial exchange.