I don't know the lady well, but given her background I assume she's intelligent. So, this isn't to degrade her but that trait in general - in what job can your role be to just tell people that they're wrong? How long would a roofer last that just stood on the ground and yelled up they were doing it wrong...even if the roofers really were? Or a programmer who denies your PR because it's wrong? Communication is an invaluable life skill. Handling disagreements with tact and real suggestions in hand will always be better received.