I think Dear Abby or her sister addressed this...
If I remember, please correct me, Abby referenced the inventor of the toilet roll as being the authority on how it should be dispensed. Can’t remember which way he said it should go.
The true question is deeper than that though. If you wish to slap the top of the roll and spill out a long pile of paper onto the floor which you then gather up and partition out as needed, then you want it coming over the top, as otherwise you will whack your hand against the wall upon which the dispenser is mounted.
If however you wish to reach for the individual sheets and politely tear them off in discrete units, then you wish it to come off from behind as the fingers of the hand will hold the roll still while you tear at the perforation, and the roll itself provides the stability against which you make the tear.
Which brings me to the real question, should the paper be torn in an upward motion of the arm, or a downward motion? If you can decide that, well then the direction of the dispenser will be clear.
If visiting a home where the roll is dispensed improperly, please take the roll off the dispenser leaving the spring and bar and other parts on the floor. Hold the roll in your hand until business is concluded, and then leave the roll in the middle of the bathroom floor.
Or just grab the end of the paper and pull out a long section and tear it with a side sweeping motion leaving a bunched end for the next customer. I realize that I have not settled the burning question, but at least my advice will get you out of the water closet and back to the rest of your life.
No need to thank me.