In the evolutionary past getting kicked out from the tribe meant death for a woman. (Men could mostly survive on their own.) So women evolved a "never accept responsibility for any mistake" attitude. I seem to recall some study claiming that in women's minds the memory of an event genuinely changes so they're blameless. In other words, when they're recounting how an event (you just observed) happened differently they're not necessarily lying. That's how it got stored in their brain.