In situations such as this, it behooves one to be proactive about one's learning. When a "teacher" is woefully unprepared to provide structured learning, it becomes your job to ask smart questions, seek out supplementary resources, and ultimately to take control of your own learning process rather than passively waiting to be fed. Some teachers take it as a personal affront if you suggest to them that perhaps their teaching style, or lack thereof, could be improved upon. In those situations, cultural and interpersonal differences can sometimes turn ugly.
While it can be a tolerable inconvenience to have a bad teacher in a collegiate setting, in my current line of work people's lives may very well depend upon my ability to provide accurate and timely translation. There simply isn't time to waste when learning a new language for the military.
We have all dealt with bad instructors at some point in our lives. Unfortunately, some of them mistake their role as a teacher for the idea that they somehow control us, or that they are the infallible lord of knowledge to whom we must bow if we expect to receive any of their precious insights. One place where I see this often, sadly, is in church.