When my wife got sick she e-mailed her TA to ask for notes from the lecture she was about to miss.
The TA's response: "I can't because it would provide an unfair advantage over the other students."
It's hard to understand what he means if you enter a class thinking the point is to learn the material. Isn't the TA's job to provide the students with material, , like notes and practice problems, to help the them learn? If he has them, shouldn't he give them out so students can be better prepared for the tests?
But when you understand that the class isn't about learning then everything falls into place. The tests aren't supposed to measure how much of the material you understand, they are supposed to measure how smart you are. Giving out good notes or practice problems might help students learn the material, but it would make the assessments test how much you practiced those practice problems and how much times you reviewed the notes, which weakens the value of the exam as a sorting device.