pigtail

I had someone tell me that the new 4-022 of 2018 says you have to pigtail all identified conductors. Where I read it as the complete opposite, where it does not allow you to pigtail identified conductors. Thoughts?

I'm trying to add another receptacle in the adjacent room, for a TV above the fireplace. (FYI: I can get behind the walls there is a avoid behind the fireplace) I have any outlet in my bedroom that has two wires coming in (one hot and one for the downstream receptacle (or it ties into a light...