If read before the section meets, they can also help instructors to identify issues that still need to be covered alert the whole class to recurring problems and give everybody tips on preventing them decide which students to call on at various points in the discussion. Responding to response papers is a necessary though time-consuming task. It is necessary because, if you do not, most students will stop putting effort into them. Briefly say something positive.
Positive feedback motivates the student and opens the channels of communication.
Note that even the last comment is positive because it tells students that you've heard them. Note too that each of these comments addresses the substance of the paper. Many students need to be told what they've done right, so that they can build on their strengths. You may frame your response as a statement or a question. You summarize X, but you haven't taken a position of your own on this argument.