I definitely disagree. For barrier=city_wall, "then the lower terrain (usually outside the settlement) should be on the right side of the line". So without additional tags, it's quite natural to drawn the protrusions on the "outer" side. For historic=citywalls , which are basically the same but more ruined so that they do not form any kind of barrier, the same logic persists.

In our case, since the walls are pretty intact, barrier=city_wall should be added together with two_sided=yes