Do graduate schools consider courses that are exclusive for one country?
This depends on the nature of the subject and the program to which you are applying. Anything that's "on-topic" for your field would of course be considered—so if you're doing a graduate program in something like philosophy, theology, history, or something in that part of the "spectrum," such a course probably would be considered. However, if you're studying something in, for instance, the sciences or engineering, or something in the humanities far removed from this—such as music—such a course would probably receive much less consideration.

Moreover, a grade of B in such a course is almost certainly not going to make a significant enough difference in your GPA that you would have been admitted if you had gotten an "A," but will be rejected because you got a "B."