Another point of view is that the traffic department realized that this was perhaps an unreasonably dangerous place for pedestrians to cross and posted a sign to that effect, in hopes of protecting pedestrians who might incorrectly judge/perceive the danger.
Pretty much every serious attempt at protecting pedestrians requires building refuges (which already exists) and devising ways to get drivers to actually slow down (as opposed to slapping a lower speed limit sign and hoping they'll do so). If you want to truly dissuade pedestrians from crossing, you need to erect a median barrier.
Merely putting up a sign sounds a lot more like the traffic department dealing with drivers' complaints of annoying jaywalkers in the least effort way possible.
