By saying that all teaching is hierarchical, the respondent does concede that lecturing is hierarchical, but this is a premise, not a major assumption. Regardless, (A) isn’t a flaw in the respondent’s argument; he can concede a claim and still disagree with the conclusion.

Like (E), the respondent doesn’t assume that moving from simple to complex concepts is effective in other academic disciplines; he explicitly states it. He says that “all teaching and learning must proceed from simple to complex,” and just uses math as an example.

The respondent is only addressing whether hierarchy is a weakness or a strength of lecturing. Any other potential weaknesses of lecturing are irrelevant.

The respondent uses "hierarchy" to refer to the difficulty of concepts, while the debater uses it to describe the power difference between teachers and students. The respondent never addresses whether the teacher-student hierarchy is a strength because he misapplies the term.

Like (B), the respondent doesn’t assume that moving from simple to complex concepts in math is representative of other disciplines; he explicitly states it. Regardless, he still never addresses whether the teacher-student hierarchy is a strength or a weakness.