Well, the article gives some reasons for the "anti-bulletproof glass" sentiment:

> The original motivation for the ban was apparently that such barriers were seen by some as "an indignity" (perhaps with a racial dimension, since many of the customers of the stores are black and many of the owners and employees are Asian).

Also, as a tourist, if you see e.g. policemen with machine guns instead of regular (or no) guns, or police cars looking like this https://en.wikipedia.org/wiki/Land_Rover_Tangi instead of regular cars, does that make you feel safer, or does it make you want to avoid that area in the future? And I can imagine seeing bulletproof glass in all stores you visit has a similar effect...