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)
Deliberate mistake: The window blind in Maroon's office changes to a sheet of tambour (as found in roll-top desks) just before Roger crashes through it. This was to ensure his outline remains perfectly in it, otherwise pieces would drop out which are not attached to the strings on either side. (00:23:25)
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.
Visible crew/equipment: Right before Eddie goes in for a closer look at the will in Marvin Acme's patty cake photo, a boom mic is reflected in the magnifying glass. (00:36:15)
Revealing mistake: Hoskins and Maroon break the news to Roger Rabbit, and Maroon gives Roger a drink. When he pours the drink you can see a clear plug in the neck of the bottle, and right before Roger Rabbit drinks you can see there is nothing in the glass. (00:23:40)
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)
Continuity mistake: In Valiant' office notice the whiskey bottle to the right of Valiant. Then Roger is about to sit in his brother's chair. While Valiant is yelling at him, look right in front of him the whiskey bottle is there, but then when he sits down the bottle is back at its original spot. (00:39:15)
Audio problem: In Maroon's office, when he says to Valiant "I want you to get me a couple of pictures to wise up the Rabbit with," notice the next shot is of Maroon from the back of his head. Notice his mouth doesn't match the words he is saying. (00:06:30)
Visible crew/equipment: When Eddie is bouncing up and down on the pogo stick at the Acme Factory, two wires are visible around his left and right shoulders; just before he bounces up into the light fixture.
Continuity mistake: After Roger springs onscreen from an underground pipeline at the Acme Factory, a steel grate is thrust high into the air, falling right in front of Judge Doom (however the shot cuts away half a second before it's supposed to hit the floor). But two shots later that same grate is seen falling from a much higher elevation again. It should have been lying on the floor at this point. (01:21:10)
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.