Ignorance diffinitly plays a big role, if we take general sources of "confidence". However with ignorance comes closed ears and eyes, so if you tell them something they think isn't true, they are probably going to hate you at some point, because "poor me can't take criticims" people think they know everything, when in reality they just heard it from random people.

That is what I call fake confidence, but others may disagree and I'm fine with that.