This is not a slip-up...stop wasting our time...they did this on purpose! If no one in the town was left-handed, the leftorium episode would have sucked and been pointless. Basically every episode, no matter where the Simpsons go, the rest of the town seems to follow...gee, that's odd?! Haven't you ever wondered why the whole town is present at, say, the soccer match...and what a coincidence, they are all sitting near the Simpsons! Hey, wait a minute...you say this is a cartoon? Oh, never mind then....
Dont listen to them Ice, this is a slip up, they can say that cartoons aren't meant to follow on, but if this is so, why does krusty still have his scars, why is lisa still a vegetarian and why is the monty burns' casino still being mentioned every now and then? it is a slip up, its just that everyone else loves the simpsons so much that they wont admit its mistakes! this is a slip up! cartoons make mistakes too! (vote quimby)
So what's the slip-up if you made the point that they are ambidextrous? This shouldn't be a slip-up if you put that explaination in your slip-up. Why is this posted again? If you say "they didn't have to buy everything from the leftorium," so what? No one cares where Burns shops. They can buy from wherever they want. Here's another slip-up---All the Simpsons characters have a very unhealthy yellow tint to their skin. They should all go see the doctor about this. Many of them don't have eyebrows either. Made they should get that taken care of.