Eddie's first line is him shaking his head and gruffly lamenting the existence of Toons. He has lumped all of them into one narrow stereotype he's formed in his head, and he lets his attitude toward one Toon affect the way he views and treats all others.
VALIANT: Forget it. I don't work Toontown.
Some people won't enter certain neighborhoods because they would be in the minority there. Eddie's prejudice toward Toontown keeps him from entering it, and makes him want nothing to do with it, or the Toons who live there.
MAROON: I got him on loan from Disney. Him and half the cast of Fantasia. Best part is... they work for peanuts!
This is a joke (elephants like peanuts) but it also serves a double meaning, showing that the Toons are used for cheap labor and are easily expendable.
BETTY BOOP: Work's been kinda slow since cartoons went to color. But I still got it Eddie. Boo boo bedoo. Boop!
VALIANT: Yeah, you still got it.
It's easy to write off an entire group as being identical, but there are differences between people within a group. If Roger Rabbit were a different movie, it might explore the tension between the black-and-white Toons and the color Toons, who exist on different social levels because of their coloring. Even without this deep exploration, we still notice that there's a sense of loss from the old style to the new. Do the color cartoons in Roger Rabbit now feel this way that computer animation has taken over?
LT. SANTINO: Just like a Toon to drop a safe on a guy's head. Sorry Eddie. Ahem. Better wait here, all right?
Even the police harbor stereotypical attitudes toward Toons as a whole. It's difficult to treat a group fairly when the police are prejudiced against them in this way.
ROGER: No wonder you hate me! If a Toon killed my brother I'd hate me too.
Roger is sympathetic toward Eddie's attitude, which makes Eddie warm up to Roger in exchange. Many people harbor prejudicial attitudes out of ignorance, and they start to question them and change them when they get to know people from the race they are prejudiced against. By getting to know a Toon, Eddie softens up his attitude against Toons.