Continuity mistake: When Jessica appears on stage, Eddie has Betty Boop standing next to him in all close-up shots, except for a wide shot of the public behind Jessica where Boop is missing. (00:18:15 - 00:19:05)
Continuity mistake: In the bar fight scene when Stupid knocks down Doom and some other guys, you can see Delores wielding a bat at the other end of the bar. In the next shot when Eddie kicks Psycho, Delores is suddenly behind the bar where Eddie is. (00:56:45)
Continuity mistake: When Eddie Valiant is in his office, and he examines the newspaper photo of Jessica Rabbit and Marvin Acme, the picture doesn't match the photos shown to RK Maroon earlier in the film, and neither does the original of the photo he looks at next. The photo shows an earlier, less sultry version of Jessica, in a halter-neck dress. (Jessica wears a strapless dress throughout the film). The DVD's Toontown Confidential special feature mentions that Jessica's look changed during filming, and the scene where Eddie takes down the Jessica photos and looks at the holiday photos of him and his brother was re-shot to show the new Jessica. Looks like they either missed the newspaper scene or felt that the view was so brief it wasn't necessary to change it. (00:35:49)
Continuity mistake: In the scene where Roger and Hoskins are moments away from crashing into a bridge in the cab quickly look at the road there is no gate in between the roads. But when they jump onto the bridge they crash right into a gate. (00:57:15)
Continuity mistake: In the scene where Valiant is sitting in the Night Club and meets Betty they start to talk. Notice she puts down her tray off to the side, in the next shot the tray is nowhere to be seen. (00:17:40)
Continuity mistake: At Maroon's office in the beginning Eddie is holding a newspaper. The way he holds it changes between the shots. (00:06:10)
Continuity mistake: When Eddie Valiant gets thrown in the garbage by the gorilla he stands up and there is some trash on his back and hat, but when the camera changes shot the trash is gone. (00:21:25)
Continuity mistake: When Eddie is looking through Jessica's keyhole his left arm is down. When it cuts he is leaning his left arm to the wall. (00:20:15)
Continuity mistake: When Maroon says "Get me a couple of juicy pictures I can wise the rabbit off with" to Eddie, you can see him standing almost face to face with him. But when it cuts from behind Maroon he is standing away. (00:06:30)
Continuity mistake: In the scene where Hoskins says, "I'm calling the cops," his eyes are following Roger as he walks across the desk, but when you see Roger he is still standing near the chair. (00:39:30)
Continuity mistake: Throughout the film the buttons on Smart Guy's jacket switch from pink to gold.
Continuity mistake: When Mr. Acme meets Eddie at the joint, he squirts the magic ink at him. The position of the things on his table keeps changing between shots. (00:15:45)
Continuity mistake: When Maroon asks if Eddie's got the will, you can see Eddie holding his coat with both hands. When it cuts he has his arm inside his suite. (01:02:55)
Continuity mistake: In the office of Maroon, Valiant gives back the paper to Maroon. The next shot he is holding it, but in the next shot its in his left pocket. (00:06:45)
Continuity mistake: When Valiant walks out of the garbage and reaches to a window in front of him, the box and bottles next to it change positions between shots. (00:21:45)
Continuity mistake: When Roger jumps out of the chair and through the window in Maroon's office, you can see the glass shatter with jagged edges at the bottom and no clean outline of Roger. The next shot shows the glass cleanly cut in Roger's shape. (00:25:00)
Continuity mistake: When Angelo is messing with Eddie you see Angelo holding an egg. When Eddie grabs him you can see the egg is suddenly peeled. (00:12:55 - 00:13:05)
Continuity mistake: In the scene where Judge Doom is going to put Roger in the dip Hoskins offers Roger a drink. He takes the drink, but in the next shot takes the drink again but not the same way; the drink spills all over the counter. (00:56:20)
Continuity mistake: As Eddy Valiant walks out of Maroon Cartoon studios in the beginning a hippo bumps into him, then walks away. About 7 seconds later you see the hippo sit on a bench causing the bench to collapse to one side and a man fly up. You can clearly see the rope that pulls the man up as well as the actual person holding the rope. (00:09:10)
Continuity mistake: When Eddie hands Roger the patty cake photos in R.K. Maroon's office, they look cluttered. Cut to the next shot and the photos are suddenly stacked neatly. (00:23:05)
Answer: There's really a lot of possible reasons he hates other toons. There's a whole Roger Rabbit book and comic book series that explain Doom's background more. In the film, he's greedy and wants to destroy Toon Town to build the freeway to make more money. In human disguise he's also seen as merciless and is just punishing toons to maintain law and order, etc. Although that's just an excuse to kill toons as well. However, not explained in the film; as a toon he was cast as the antagonist in cartoon films until an accident one day left him thinking he was an actual villain (as opposed to just an actor playing one). That's when he began his life of crime, including killing Teddy Valiant. So his hatred of toons is more about him being evil and not a personal vendetta against them, like Blade's motives.