Strictly comparing the bottom left quadrant (the "lovable fools") to the upper right quadrant (the "competent jerks"). Everyone would rather work with someone who is likable and competent.

In a large company, dabent's "BigCo", as long as you're getting your paycheck, an easy-to-along-with but less competent coworker may be less of an impediment to your ability to do your job than a competent jerk. It may also be that the article's authors were not using the same concept of "difficult" as Fred Wilson was.