I still maintain that it crosses from bad teaching method into abusive when it crosses from "Telling your daughter to go away and learn how to use a can opener because you have a jigsaw puzzle" into "Forcing your daughter to learn on her own how to use a can opener while you tell stories about how great you are at opening cans with all manner of tools, and when she tries to abandon it you tell her she must do it or she doesnt get to eat and also she will be responsible for you not eating tonight either"

At that point its putting a lot of emotional pressure on a 9 year old who cant just tell you to fuck off and throw the can at your head, or go to the fridge and just grab something, a 9 year old doesnt have the emotional maturity or confidence to actually resist things like this from a parent, and having that powerlessness demonstrated with threatening to withhold food from them when they have been hungry for at least a few hours already is something that can and probably will stick somewhere in the childs mind, either as a learned behavior towards authority or as a point of resentment.