I understand that one can't prove, evidentially, the veridicality of properly basic beliefs such as objective moral values.
We can, however, give examples. Consider this horror story of rampant rape in the Demcratic Republic of Congo, written by Fiona Lloyd-Davies.
"Eastern Congo has been called the "rape capital of the world" by U.N. Special Representative Margot Wallstrom. Reports record that 48 women are raped every hour. I have been working in the region for 10 years and have seen a tragic development in this unpunished crime against the heart of society...
... A week hearing terrifying stories of torture and rape. Multiple rapes. Violent, brutal rape. Rape with sticks and guns, even bayonets. Women told me of their daily choice -- to stay at home and face starvation. Or, go out to the fields for food and be raped. Most women chose the latter. It had become the norm...
... I returned to make a film about rape and found a disturbing new trend.
Women told me how they expected to be raped. Not once but many times. The women I met, spoke of gang rapes, three or four times. Sometimes it was "only" two soldiers, more often gangs of men,10, 20, over and over again. Many had conceived children and the girl children, some just babies only a few months old, were being raped as well...
... women survivors... are living with the consequences and stigma of rape. Not least one particular woman, Masika Katsuva. She's tiny, barely five foot tall but is a giant of a personality. Her story has inspired many of us, it is so bleak but also hopeful because she's providing an answer to these women.
... Like so many women survivors, she too was rejected when she and her two teenage daughters were raped by militia men. Her husband was murdered in front of her, chopped up and she was forced to eat his private parts."
That... is wrong. Morally wrong. Objectively wrong; that is, wrong for everyone. Anyone who thinks it is not morally wrong is just as mistaken as someone who thinks it false that 1+1=2.
Thank God for Masika Katsuva.
See Lloyd-Davies's film on Katsuva's work to hep DR Congo's rape survivors to find healing and an independent income through farming