Can anyone explain this George Carlin quote?

Carlin once said on Real Time with Bill Maher "When fascism come to America... it will be Nike sneakers and smiley shirts. Smiley smiley". I understand what he means by fascism coming to america, and I understand the nike reference, but what I don't get is the "smiley shirts" reference. Does anyone know know why he mentioned that one particular item?