Also maybe she was “horrified” as this dirty dancing/sexual act might have looked like rape to her. That could also be why they had to define the act as “consentual”.
That is the most reasonable reply thus far...and yet I think if that was the fact, remaining rational and keeping a level head would have been in the best interests of the woman, her children and the victim.
BTW, I'm not saying I've never been horrified or I've always been able to cowboy up through every situation I've eveer been in. It's precisely because I haven't that I can attest to the fact that when the person in charge (in this case, mom) overreacts, panic quickly infects those about them (in this case the kids), and seldom does it do much good for anyone involved.