The primary sales demographic for Toys R Us is children. Although I agree that some parents need to do a better job of watching their kids, I also believe that a store catering to children, has a responsibility to take reasonable steps to consider what items they display.
I don't have children, but I remember how careful my own parents were to shield me from things that were inappropriate for children to see. My hunch is that if I was still a kid now, with my same parents, and we walked into a toy store and saw those "toys", my parents would have quickly whisked me away to another aisle. And they probably would have marched up to the customer service desk and demanded to see the manager of the store, to complain about the offensive items.
If the toy store insisted on carrying these items, then they should have been kept them in a separate area of the store (a cordoned off area with perhaps a turnstyle) that required age identification from customers to enter (adult only, or 16+).