Having also studied math, my experience is that they probably didn't. Less than 1% of the students I have ever come across in any subject have cared enough about the sheer act of learning to ask questions. The rest were there for a piece of paper, and nothing more.
Being right, does not endow the right to be rude; politeness costs nothing. Being unknowing, is not the same as being stupid. Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence. Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.
When I taught math, I had a sure-fire cure for this.
Every class started with a 10-minute "question and answer" period. The rule was that someone would ask questions and someone would answer. The unstated rule was that you really, really didn't want me asking questions. They only made that mistake once. ;-)
This may only work in a class which is small enough that every member has a realistic fear of being picked to answer a random question from the previous day's class.
This worked really well with cumulative homework sets. In homework people kept on being reminded of things that they didn't quite get earlier in the course, and since they were looking for things to ask me anyways...