How many examples of the consequenes of disarming people do you need?
She could have mentioned the Khmer Rouge and Cambodia. The Ottomon Empire disarmed its Christians prior to the Armenian genocide. Idi Amin disarmed Uganda prior to the atrocities there. Stalin did the same in Russia. The genocide in Darfur also comes to mind. In Sudan it was impossible for black citizens to own guns but the Arabs shooting them were able to get guns.
In the American South, blacks were denied the right to own guns. I wrote an article about racism and American gun laws. I could also go into the history of medieval China, Japan, and Europe and how keeping the peasants disarmed helped the aristocracy to keep them powerless and oppressed.
How many examples do you need?