As a none native speaker I don't get it... Is it some kind of slang word? Like in german you can insult a skinny person by calling them a leek.
In case you are serious - "vegetable" is a really negative way of calling heavily disabled people.
@retrolasered @Tb0n3, completely immobile and nearly braindead it also fits many politicians today, without which unfortunately they are designated as handicapped.
i think Demdaru covered the way it's used in this meme but FYI it's also used for comatose patients (see german: "vegetieren")
