It's good to show the wrong way intentionally here. We don't want to confuse people that this could be a real house, with a real bathroom, so I can appreciate that they intentionally do things wrong so you could walk in, see the TP is in the wrong position, and instantly go:
"I'm in a Lego bathroom, this is not real"
And boom, no more being trapped inside the lego bathroom.
At one point the toilet roll holder my landlord put in fell apart. So I made a new, better one. A toilet roll holder that actually keeps enough distance from the heckin' darn wall
So it doesn't matter, my paper is clean either way!