Why doesn't Zero want to be a ward of the state in Holes?

Zero doesn’t like the way “ward of the state” sounds, but does not know what it means. 

To be a ward of the state means that you have no parents, and you are in foster care.  Zero’s mother left one day and never came back.  He has some memories of her, but doesn’t know what happened to her.  He clearly misses his mother and wants to see her again. 

Zero’s real name is Hector Zeroni.  When he and Stanley go missing, the Warden and Mr. Pedanski decide to erase all records of him so that no one will ever know he was there in the first place.  They think no one cares about Zero.  Stanley overhears them talking about it when they sneak back. 

"You sure he has no family?" the Warden asked Mr. Pendanski.

"He's a ward of the state," Mr. Pendanski told her. "He was living on the streets when he was arrested." (Ch. 31) 

Later, Zero says that he doesn’t want to be a ward of the state, even though he doesn’t know what it means to be a ward of the state. 

“… If they'd found out I didn't have a mom, they would have made me a ward of the state."

"What's a ward of the state?"

Zero smiled. "I don't know. But I didn't like the sound of it." (Ch. 41) 

Zero and Stanley have some old family history in common.  This is how Stanley is able to break Madame Zeroni’s curse.  The curse was supposed to be the result of Stanley's great-great-grandfather stealing the pig.  He was supposed to carry her up the mountain.  When Stanley carried Zero, that broke the curse.  Zero was also the one who stole the shoes that Stanley got sent to Camp Green Lake for.  He used the money from his share of the treasure to hire a private investigator, who found his mother.