I would hardly say that "nobody" listened. Many times several posters tried to reroute the conversation by reminding folks that LE said to ignore the hat. The conversation continued.
Still, the posted article is an interesting one and worth making note of. Originally, we were told to overlook the hat. People were speculating as to why we were told to ignore it. They also continued to fixate on the type of hat, insistent that it was a rare kind that hardly anyone wore (which is not true; they're insanely popular at the moment).
LE should have had the sketch artist depict the actual hat that BG was wearing, or else not put one on him at all. Once you've seen something, it's hard to unsee it and, as another poster pointed out, it could have led to someone in BG's life ignoring the sketch altogether because the hat didn't look like something he would wear.