Continuity mistake: After Eddie and Roger spring Benny the Cab from the Toon Patrol's car, the amount of sunlight being cast changes instantly between shots. (00:57:50)
Continuity mistake: After Roger has a violent reaction to R.K's drink, a decanter bursts open and leaves bourbon all over the blinds. But moments later when Roger crashes through the window and leaves an outline of himself, the blinds are completely dry. (00:24:20)
Continuity mistake: Eddie's arms change position between shots after Roger drinks the bourbon and collapses face-first onto R.K. Maroon's desk. (00:24:15)
Continuity mistake: During Donald and Daffy's piano duel at the Ink & Paint Club, the grand piano's lid opens and closes on its own while Donald is performing simultaneously with his hands and tail. (00:16:40)
Continuity mistake: After saving Toon Town from Judge Doom, Eddie lowers the giant hook and starts untying Jessica and Roger. He throws one rope offscreen and the other just slips from the hook on its own. But in the following shot no rope can be seen on the ground directly below the hook where it should have landed. (01:33:10)
Continuity mistake: When Judge Doom cracks Greasy in the head with his cane, he lands in a stack of Acme eyeball boxes. Some of the boxes in the background change their positions and locations in alternating shots while Doom is talking about Acme's will. (01:17:10)
Continuity mistake: Check out the style of Eddie's shoes when he's flat on the floor of Droopy's elevator as it's going up. Notice how he's got a different pair on his feet minutes later while gazing down at Judge Doom's gun in the back alley. (01:11:30 - 01:14:15)
Continuity mistake: When Roger is in Eddie's apartment hiding from the Toon Patrol, a picture on the nightstand by the pull down bed changes positions on its own. (00:37:20)
Continuity mistake: In the scene where Eddie stops his Plymouth to get out and look into Toon Town's tunnel, the passenger side vent window cranks itself open between shots. (01:07:55)
Continuity mistake: Before Eddie drives his Plymouth into Toon Town, he breaks out Yosemite Sam's gun for the occasion and loads it with the animated bullets. The gun starts off in his right hand. But by the following shot when he gets ready to take a swig of Wild Turkey, it has instantly switched over to the other. (01:09:05)
Continuity mistake: While Valiant is driving through Toon Town, there's no continuity between what he sees ahead, and what is seen in the car's rear window seconds later.
Continuity mistake: After Eddie has crashed in Toon Town he gets out of his car and casts no shadow, and looks as if he's floating. Later on he does cast shadows. (01:10:45 - 01:13:30)
Continuity mistake: At the end of the film, when Delores and Valiant are about to kiss, she has her right arm down. A second later, from a new angle, it's up. (01:35:35)
Continuity mistake: When Mr. Acme is killed with a piano, there's a cop next to a briefcase taking pictures of the crime scene. A frame later the cop is 1 meter away from the briefcase. (00:29:05)
Continuity mistake: When Baby Herman's cigar falls to the floor its position changes between the first and the second angle in half a second. (00:35:35)
Continuity mistake: When Valiant and Roger are in the cab trapped in the alley, the distance to the exit of the alley keeps increasing and decreasing wildly as well as the distance to the police car in front. (00:59:00)
Continuity mistake: When the spray-machine is about to kill Roger and Jessica it smashes a brick wall with some lettering and a thick white line painted below. In the close-up the lettering and the line are gone. (01:32:25)
Continuity mistake: When Baby Herman slides through the kitchen floor towards the fridge he stops with most of his butt on a black tile. When the angle changes he is sitting on a white tile. (00:01:30)
Continuity mistake: During the alleyway chase, a trashcan on the side keeps appearing and disappearing through shots. (00:58:50)
Continuity mistake: When Eddie crashes his car in Toon Town, from the inside we see that there's nothing in front of the car, but when the angle changes we can see a huge mess around with lots of people surrounding the car. (01:10:35 - 01:13:30)
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.