Peraski: Although driving gas-guzzling automobiles produces a greater level of pollution than driving smaller cars, those of us who drive smaller cars when we could use a bicycle cannot speak out against the use of gas guzzlers.
Peraski's Claims
1. Driving gas-guzzling automobiles produces a greater level of pollution than driving smaller cars.
2. Those of us who drive smaller cars when we could use a bicycle cannot speak out against the use of gas guzzlers.
3. We would be revealing our hypocrisy.
Jackson's Responses
1. No disagreement. In fact, he seems to implicitly agree that gas-guzzlers produce more pollution than smaller cars, since he alludes to "greater sources of pollution"
2. Disagrees. Peraski said that people who drive small cars can't / shouldn't speak out against gas guzzlers (because they could do even better for the environment if they swapped their small car for a bike). Jackson is saying that people who drive small cars should / can still speak out against gas-guzzlers.
3. Agrees that it is somewhat hypocritical to complain about emissions if you're still driving a car instead of a bike.
Goal
In this case, we have an explicit claim that the 2nd speaker disagrees with, so we should be able to head to answers looking for