I take a picture, facing front, and I get a reduplication of the reality in front of my with the right and left sides equivalent between earth and digital. However, once I step over to take a selfie picture reality gets reversed on the digital end, right to left and left to right. Why?
I'm a little confused by what you mean by reality getting reversed. It may help if you provide pictures.
Possible scenarios: You may be changing the orientation of your device causing your camera to assume which way is up and down. Or You may have a orientation lock on your device as a whole, that is affecting the camera Or You might just be seeing your self from the view/ direction that your camera sees you.
In actual your selfie isn't fliped by Apple, in fact Apple is probably one of the very few Makers who keeps it the way it should be. But, even still if you want to change the selfie mirroring, then there are plenty of apps on AppStore as well. I am providing link for one of them . Mirror Selfie App