Doing the right things is a mechanism that promote our survival.
Humans needed to learn to live in society to be able to survive. It is not possible to survive in society without any rules.
IE : Killing member(s) of the tribe will have disastrous effect on the survavibility of the tribe
And I don't know if fundies in general thinks that the concept of right and wrong are exclusive to us human, because it isn't so.
Even my dog knows right from wrong. When I go back home and I don't see him running toward me, that because he couldnt hold it in anymore, and must of pissed somewhere in the house. He comes then slowly towards me with the tail between his legs, he knows he did wrong.
It is instinct, "right" happens to be what promotes life in society and "wrong" what destroy it.