I understand where the martyr/tyrant concept for [male] ISTJs came from, at least in regards to the ones I have had as friends and/or acquaintances.
For many, there was an odd mix of passivity and not wanting to break the peace, coupled with very strong opinions about the way life and/or the world should be. (Often the topics of politics or religion will bring this conflict to the surface.) So they feel like the world is changing around them and things are going to hell in handbasket (either in their home, or in their workplace, or in society, or in their religious culture, etc... some sort of "institution" of which they have a clear internalized Si definition).
But when it comes to personal issues and strong emotions, they usually try to rein them in and not express them, because of the "illogic" -- and stuff them, become martyrish sometimes and usually just grumbling about their fate. When they finally cannot deal anymore, they can become very demanding and tyrant-like, clamping down on everyone else. And then they're prone to stuffing it again, if the demands do not change anything, going back to the martyr extreme and grumbling.
Other types do undergo similar stresses, but tend to react differently or not as extreme of a flip.
For an ISTJ tyrant with some martyr features, you could look at Ricky's father in "American Beauty," who actually would be considered actively abusive. But most ISTJ males are not dysfunctional like that, they just have the same level of issues as any other type.
Basically, the response depends heavily on the ISTJ's ability to deal with change in the external world, compared to his internal idealized world.
I cannot describe female ISTJs too well because I have only really known one in real life, and known OF another... and I think the female brain and socialization helps them to better mediate between the internal and external worlds and communicate better. The men tend to think more just in terms of power ("Do I assert myself, or do I just sit passively and hold my tongue?"), whereas the women are more willing to not internalize the entire thing.
PM's post was good, but this factor must also be taken into consideration.