As you specifically were looking for a hook here, I would add onto what was submitted by jcooper20. Yes, the contrast here is that Atticus is willing to openly show his distaste for the racial divide in Maycomb, while Dolphus (although clearly not agreeing with it either) tends to portray himself as a drunk to avoid this confrontation.
Perhaps a good hook would be to reference the paper bag in which Dolphus keeps his Coca-Cola: While Atticus Finch puts himself in the foreground, Dolphus Raymond cloaks his ideas about Black-White relations as he cloaks the Coca-Cola from which he constantly drinks. Both men share similar view about what race relations could look like in Maycomb. However, Atticus Finch chooses to fight for his ideals, while Dolphus Raymond chooses, instead, to hide his true feelings.
Hope this helps!
You could first contrast the way they each deal with society's prejudices and then compare how their actions are alike.
Atticus does not believe blacks should be treated differently, he is not prejudice. He fights for Tom and shows the city of Macolm his beliefs.
Dolph does not believe blacks should be treated differently, but he hides his beliefs behind what the city of Macolm thinks is a liquor bottle so his behavior is "excused."
Each fights the social norms of the day. Dolph by his actions and Atticus by his defense of Tom.
Atticus shows backbone, Dolph shows cowardice (takes the easy way out).