Many people have a fascination with cleaning their body parts and looking at the cleaning product to confirm that the dirty stuff is gone. Toilet paper gives you that’s satisfaction.
Or, would you go wash them in the sink...
In this case, our noses are probably a better metric. If you used your fingers to touch your ass after wiping and then smelled them, would you wipe more with dry TP, or would you wash it off another way?
It is odd to me that anyone would argue that TP would do a better job in this case.
The Qorantos/Trainwrecks conjecture