You are correct. Aside from chemical analysis and computer programming there is no way to take subjectivity out of judging. It is very interesting, however, that the top teams build up enough of a popular flavor profile and perfect the duplication of it sufficiently to almost always stay in the top finishers. Those of us who compete less frequently don't have as much consistency.
As to judging what is not your "taste" the best method is an open mind. When you judge think not "this isn't what I like" but think "is this good barbeque whether it fits my preferences or not". The best judges don't judge to their own tastes, but instead judge to what presents their palate with excellent preparation. Once you begin active judging you'll discover that there is a distinctive "Contest Style" of barbeque taste, tenderness and appearance. There isn't much regionality. There isn't a lot of innovation in new directions (I've opined that in some Bull Sheet articles). But there is intense focus on contest style. It is legitimate despite its faults.
You seem quite sincere about judging and judging well. Here's a link to a series of articles I wrote on the subject a while back -- they were widely discussed and distributed in KCBS Rep circles.
http://www.thebbqforum.com/bbq-forum-comments.htmlHub
