People under a certain age (16, 14, don't know the best) shouldn't be legally allowed to use ad-backed social media, or be allowed in stores without parents bei

People under a certain age (16, 14, don't know the best) shouldn't be legally allowed to use ad-backed social media, or be allowed in stores without parents being present. Social media being defined as anything with a comment field. Stores being defined as any site that accepts payment or a building that has a cash register. If you are in a legal class (minor) that says you are not legally allowed to work or be self-sufficient, why are you allowed in a place/website that primarily exists to sell you things or engage with a place/website whose primary business purpose is to expose you to ads in order to sell you things indirectly?