Why does the letter state that johnny and ponyboy are famous outsiders?

In the letter, Johnny and Ponyboy are referred to as "famous outsiders" because they represent the struggles and resilience of marginalized youth in their society. Their experiences as members of the Greasers, a group often looked down upon by the wealthier Socs, highlight themes of class conflict and identity. Additionally, their story resonates with broader issues of belonging and the search for understanding, making them relatable figures for many who feel like outsiders in their own lives.