Instead of using Myers-Briggs as a tool for understanding, you've just it to pigeonhole someone based on one negative characteristic (which lets you disregard his opinions) and then blamed his personality type for "a lot of the world's problems."

Tools like Myers-Briggs are great for looking at yourself, understanding your strengths and weaknesses and learning to be a better person. However, when you start using them as weapons, the focus becomes other people's problems. I guess the benefit is you don't have to worry about self-improvement anymore when a personality typing system makes it so convenient to place the blame somewhere else.