You have no idea what law school is like. You don't learn anything in class. You get more confused and listen to hypothetical situations that have no answer and indirectly discover whether your professor has certain leanings towards various types of analysis (e.g. if they're the law and econ kind, social utility kind, favor strict interpretation, etc.) all of which you can learn while idly listening (or even just asking the other people that have had your professor).
And re: lectures.. we don't have lectures generally. We have the socratic method which is like a sick hazing method where professors batter you with questions until time is up or you start crying (okay, exaggerating slightly, but..). Most likely the impetus behind this is because the professors are sick of students who aren't paying attention in class (and we can't skip because there are ABA requirements regarding class attendance) and they get called on to recite the facts of, say, Frigaliment Importing Co. v. BNS International Sales Corp. and have no freaking clue what's going on (because no one really cares about the difference between hens and stewers and their respective market values. We were satisfied at the "you assume words are defined as trade usage unless explicitly specified otherwise" rule), and then the professor stands there for 10 minutes while the person frantically flips around in their books trying to figure out how to answer the questions.
And (responding more to other people below), if the professors don't want to waste class time, they should go "Gosh, Fred doesn't know the answer, wasn't paying attention, or just didn't read for today" and move on to their next victim or one of the gunners with their hands in the air who are more than to willing to recite the facts of the case and then explain in excruciating detail why they think it's wrong or right or just talk about something random and tangentially related, rather than trying to embarrass the person they decided to pick on.
Don't tell me how hard you work. Tell me how much you get done. -- James J. Ling