Continuity mistake: When Eddie goes to meet Maroon with his accusations, Maroon is holding a distinctively brass colored gun. When Eddie attacks him, the gun is released by Maroon, and it instantly cuts to a shot of Eddie on top of him, an identical gun in hand. Then when they get up, Eddie tosses the gun aside. When Doom shoots Maroon through the window, Eddie dives for cover and once again the gun is amazingly in his hand. (01:06:20 - 01:07:15)
Continuity mistake: When Eddie pours out his whisky, the way he holds the bottle changes between shots. (01:06:35)
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: In the scene where Eddie pauses at Toon Town's entrance to load his gun, the Plymouth changes its position on the road relative to the double-yellow lines. (01:08:00 - 01:09:25)
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: A few seconds after Eddie makes the big turn in Toon Town's tunnel, his right thumb noticeably changes its position on the steering wheel between shots. (01:09:50)
Continuity mistake: Upon entering Toon Town and crashing into Jessica Rabbit's Packard Eight, Eddie's steering wheel rotates all by itself - as indicated by the spoke positioning itself between his hands all of a sudden. (01:10:35)
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)
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: 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: After fooling Lena Hyena with a road divider, Eddie's necktie blows over his left shoulder. But once the angle changes, his tie is suddenly hanging down again like normal. (01:13:30)
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: Near the end in the Acme Factory, the weasels tunnel through the wall and say "Toontown is on the other side of the world, boss". Understandable because of the portal link between the two "dimensions". But while the wall they're tunneling through seems to only have about ten layers of bricks, when the Red Car crashes through it, it alternates between one layer of bricks to three and back and forth. (01:18:00 - 01:32:30)
Continuity mistake: After unveiling the dip machine, Judge Doom explains its functions while waving his cane in the air. But in the following shot his cane is planted firmly on the floor instead. (01:19:15)
Continuity mistake: When Roger blasts out from beneath the Acme Factory grate, Judge Doom lifts his head twice in successive shots. (01:21:05)
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)
Continuity mistake: When Roger goes to the Acme warehouse, he brings the gold-plated gun that was in Eddie's car after Eddie took it from RK Maroon. This is a real (not-animated) gun, and when Roger is talking to Benny before going into the warehouse, he's holding a real (non-animated) gun. After Roger bursts through the drain, the gold gun he's holding is animated. (01:21:25)
Continuity mistake: As Roger and Jessica get tied to the hook, Wheezy and Stupid switch places between shots. (01:22:15)
Continuity mistake: After Greasy starts up the dip machine, the number of ropes tied around Jessica's midsection changes from two to three within a couple of shots. (01:22:30)
Continuity mistake: Towards the end where Greasy laughs himself to death behind the dip machine's wheel, from the point at which he falls out until his ghost appears, the driver's side door window cranks itself halfway open. (01:25:30)
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.