I don't think it's the BJCP's fault per se. Rather I look at human nature.
A lot of judges, when new, are a bit unsure of their skills. And we definitely have some higher-ranking judges who are a little overbearing with the "why the hell did you push this terrible beer?!" in a mini-BOS setting.
I believe being unsure of one's skills leads to a "low-hanging fruit" or "Fault-Finder" type of judge. I just wrote about this in a cider article last night. Certain flaws make a decent percentage of judges just tune out. "What is this s***, butter?! How dare they! The horror, the horror - I'm done!" - and they give the rest of the beer (or mead, or cider) short shrift. That's not OK.
The easiest way to not have anyone question your judge skills is to ding the beer and not have it move on. So we have people looking for reasons to dislike the beer, instead of looking at its merits. People who see styles as extremely narrow, rather than existing on a continuum, with some overlap between styles. And if we don't address it, those judges often become experienced judges with the same skewed perception of flaws and their severity.