Why do locals turn right where tourists go left?
The short answer
Residents navigate by a mental map built over years. The wider street is often the congested commercial route. The narrow dark passage is the empty residential shortcut.
The navigation is social. Doors that look closed are open. Passages that look private are shared shortcuts tolerated by families along them. A resident nods at the woman on the step and walks through what you'd perceive as her front garden. You cannot follow because you don't have the social permission.
When a Moroccan says "it's close," they mean close by their route. When they say "straight," they mean the general direction, not a literal straight line.