In utilizing leadership models and personality assessments, do project managers cross a line between good management technique and manipulation?

In presenting this material to a large number of graduate and undergraduate students, I am often asked if the models that managerial science has developed have a tendency to promote Machiavellian manipulation rather than good leadership. Now I am turning the question over to you.

Now that you have identified your Myers-Briggs type, think about how you, as a project manager, might use the knowledge of the personality types of other individuals? Think about information generated by the other model and how that information might be used in good leadership or and when it might be used to manipulate individuals of perhaps even be considered leadership for evil intentions.

When we listed some of the Best Leaders, we found that not all of the leaders (Adolph Hitler is one example) had positive or moral goals. These Best Leaders used these models to manipulate, or exploit, groups and individuals to less-than-moral goals and objectives. Project managers face the same moral predicament; that is, when are you using these models for good and which of these models has the greatest tendency toward being used to manipulate?