These bad professors would take forever to grade, if not that then they would do what you describe and give us irrelevant information and odd spiels about whatever thing was bugging them in the politics world, or maybe even something their dog or cat did the week before that totally delayed them getting us our grades or assignments. I remember in my statistics course the guy spilled coffee all over our written mid terms! How careless.
I, not much unlike yourself would try and find any easy way to get ahead of the curve. Now, a common theme among these bad professors is definitely giving irrelevant information, being lazy, or even completely disorganized to no hope. With all these mistakes, they end up making huge mistakes in their own syllabus. You have no idea how many terrible things these people would do in their own work!
A neat little thing I found that nearly all bad professors do is list the exact material they would cover throughout the course, maybe not always week by week but an overview of the material we would touch on. How silly of them.
That's not even the kicker, these bad professors would even list the exact place where they took things from. Hilarious indeed. It was usually under some strange section called 'Required Course Materials' or 'Recommended for Review'. These suckers couldn't be any worse at their job, practically giving us the answers.
When I figured this out, I started going all in with the cheating. After getting the syllabus I would get this thing and read it from the beginning to the end, trying to cover as much material going topic by topic to be covered in the schedule. I could finish the course in practically 2 weeks, didn't even have to wait for these lectures that were pretty much a waste of time after going through it. By the 3rd bi-weekly lecture, I would have learned the entire course. Those fools never knew what hit them either, I would ace their assignments and finish exams before anyone else. I would even stop showing up to class with how adept I was at cheating. No one even suspected that I was cheating.
I would try and get others to follow my path. They would always ask how I did it, how did I, who really wasn't all that special, or smart, get so many A's. Even in spite of the quality of instruction.
The answer was always the same - read the textbook!