I get the feeling that a one-dimensional view of directed/purposeful behavior (weak -> strong) is constraining the discussion. I do not think we can take as obvious the premise that biologically-evolved intelligence is more strongly directed than other organisms, which, in many different ways, are all strongly directed to reproduction, but it seems there are more dimensions to intelligent purposeful behavior. There are some pathological forms of directedness, such as obsessive behavior and drug addiction, but they have not come to dominate in biological intelligence. We generally pursue multiple goals which cannot all be maximized together, and our goals are often satisfied with some mix of less-than-maximal outcomes.
So, even if coherence does imply a force for goal-directed behavior, we have some empirical evidence that it is not necessarily directed towards pathological versions - unless, of course, we have just not been around long enough to see that ultimately, it does!