I would reccomend that your parents see a family theropist. (My dad is a psychologist, and it's not a bad profession)
It sounds like they are paranoid and overprotective, which explains why they foster children. You see, I believe that their fostering is a way they may seem to "quench" some kind of Autoritarian need. They seem to also be over-asserting their power. Plus, if possible, try to convince them that they should see a professional. Their condition they are exposing you and the fostered children could not be healthy.
On top of this, they are hypocrits. Most people will play video games for a little time, then go on with their daily lives. They are saying that you need to do work more. You are still juvenile, yes? If so, you are entitled to liesure just as they are. Although they may have jurisdiction over you, they are enforcing labor unsuited to a juvenile.
Statistics have proven that this kind of enforcement from parents causes social problems more often and to a greater degree than playing video games, therefore, their claim that you will end up as a legless, homeless man is false. They are blindly playing you into a worse situation.
