I guess I don't even understand why you're questioning your response or what we'd do. Kid throws something, parent/adult tells kid to knock it off (great phrase BTW. One of my parent's favorites). End of story.
Kid does it again then toy gets taken away (if it's your own child) or kid gets sent home.
There's no need to psychoanalyze anything, question kid's motive for throwing toys, or speculate about the kid's homelife. Seems like a no-brainer to me.