They hate themselves because they rightfully are ashamed.  Shame is a natural human emotion that manifests when one realizes one is doing something wrong.  Nobody needs to be taught to hate fat because it's an inherent human instinct to be disgusted by it just as the thought of eating rotten food or excrement is disgusting to a human. They either delusionally convince themselves or simply just lie that finding fat disgusting is a taught behaviour or due to the patriarchy or whatever other  13fa   nonsense they can think of, in this way they believe they can ignore the shame they feel and continue in their behaviours by placing the blame on external factors.  Essentially it allows them, in their own minds, to not have to take any responsibility for their own actions.    Classic fatty!