These are just some bullet points (my new favorite thing) from Shepard Fairey’s extensive blog post

• I am fighting the AP to protect the rights of all artists, especially those with a desire to make art with social commentary.
• the photograph is just a starting point.  The illustration transforms it aesthetically in its stylization and idealization, and the poster has an altogether different purpose than the photograph does.
• I did not create the Obama poster for financial gain. The poster was created to promote Obama for president, and the revenue from poster sales was re-invested in more posters, flyers, stickers, etc..

Read it all here