For me, the images of magazine covers were missing the diversity of the U.S. society and, with my own bias, I focused on African Americans and African born images. Even the one picture of Kanye West was airbrushed to make him appear lighter skinned and glowing. Some of the women in the room honed the ways girls were portrayed as plastic and boys as athletes and team players. The exercise did exactly as it should - it brought us awareness of how our students are bombarded with images (and music and movies and icons and toys and ideas) that are counter to the mission of being intellectual and critical.
This is why I found the exercise to be extremely productive. Our group has though hard about whether it is possible to teach critical thinking skills and I believe it is lessons like that which help them grow more astute to EVERYTHING around them (and is another stellar indication that jumping beyond textbooks is extremely important...youth need to read all texts, including those that are not canonized and the ones they've yet to write).