Conversation so far:
Who took the famous photo?
Morris Berman.
When was the photo taken?
September 20, 1964.
What was the photo of?
of the Pittsburgh Post-Gazette.
What was he doing in the picture?
photographed helmet-less, bloodied and kneeling immediately after having been knocked to the ground by John Baker.
Was he injured?
CANNOTANSWER.
What else happened with the photo?
Post-Gazette editors declined to publish the photo.

Question: Why didn't they publish the photo?
Self-contained rewrite: Why didn't Post-Gazette editors publish the photo of Y. A. Tittle?