It may be simply that, remembering my own teachers, the oddballs, the true believers, the zealots stand out. But it goes against my own practice as a teacher and that of most of my colleagues. Most of us see ourselves not as purveyors of views but as challengers of assumptions. The second thing that surprises me in the comparison is how both approaches seem to merge when we think hard about the actual practices and purposes of teachers. Real advocates and devil's advocates alike do not want to build in straw.
Solid foundations matter more than anything else to people with a passion for ideas.
The most zealous true believer, setting out to convert her students, does not want them to come round too easily. My two instructors in the work of the mature Karl Marx didn't want us to buy in so much as they wanted us to listen and possibly heed a powerful critique of our own society and its foundations. They were believers, yes, but they didn't just want us to fall in with their beliefs. As they saw it, they had worked at them, examined alternatives, tested concepts and assumptions against study and experience. I have had many great teachers, but few of the great ones were people with whom I agreed in the obvious points of politics or morality.