I don't bother with people like that. Anyone who thinks everything that they say is pure fact and that they are always right is a moron. It amuses me when people seem to think they know so much more than other people when while they don't even know what they are saying. Most likely this fool was scammed for his bitcoin and instead of taking responsibility he blames bitcoin.
Me too, these kind of people of who do not own up to their mistakes and not admit that is their fault is a hopeless cause, imagine getting screwed by someone and you blame the medium you used for the transaction instead of yourself and the scammer, that is the weakest mindset that I can think of, having the ability to be ignorant about your mistakes is something that is done through self discovery.