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)
Audio problem: In the scene where Valiant is outside and looks over to see the brooms cleaning, notice the bird on the bike coming towards the camera. You hear a bell ringing as he goes by but there is no bell on the bike. (00:09:10)
Audio problem: The first thing we can hear as Eddie walks upstairs into the bar is a rack of pool balls being broken. But two seconds later he greets his buddy Harry, and at this point we can see how all of the balls have settled and a player is lined up and prepared to take his shot at the corner pocket. It takes more than two seconds for a rack of pool balls to settle. (00:11:20)
Audio problem: When one of the bar patrons talks about Earl's two week notice, he says "Put the poor guy on two weeks' notice," but at the point where he says "guy" his lips are forming an altogether different word. (00:11:40)
Audio problem: In Valiant' office after Roger reads the letter and Valiant says, "Why didn't you just leave the letter there." Notice Roger standing on the bed, you hear him talking, but his mouth doesn't move. (00:38:45)
Audio problem: When the Toon Patrol shows up at Eddie's door in search of Roger, they start knocking and the door shakes in response, but sometimes no sound can be heard to correspond with the door's movement as they knock. (00:40:45)
Audio problem: As Eddie walks into the bar with Roger stuffed into his coat, you can hear somebody shooting pool. But only two seconds later Eddie walks past the pool table and, here, we can see one of the patrons actually passed out and laying down on top of it. It would be impossible to shoot pool under those circumstances, which means the pool ball noises were dubbed over. (00:43:20)
Audio problem: In the scene where Hoskins and Roger are going into the sceret room Dolores says, "oh swell," but her mouth doesn't move. (00:44:00)
Audio problem: In the secret room where Hoskins and Dolores are hiding Roger right before Hoskins hits his head on the lamp he says, "crazy tunes," but his mouth doesn't move. (00:44:25)
Audio problem: In the scene when Eddie goes to give Maroon the fake will, Maroon says "I'm a cartoon maker, not a murder!", when he says "Murder" his lips aren't moving at all. (01:06:35)
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.