Max is a lawyer and a Jewish American.  He represents Bigger since he is in a position to better understand what Bigger is up against given his Jewish heritage and the racism and antisemitism he has suffered.  Even though Mr. Max is virtually the only person who understands Bigger, he still leaves Bigger absolutely mortified by what he has done and the extent that American society has corrupted this otherwise decent young black man.  The savage brutality of American racism shocks him, and through his speech at Bigger's trial, the reader.