The definition referenced in the post is a special case. It talks about a situation where people form a cached overly negative opinion, and apply it to a whole group. This makes them systematically wrong about the individuals of that group, who are not as negative as the stereotype, and thus this situation constitutes a bias, systematic error of judgment.
The post is poorly written, its topic or contribution are unclear.
The definition referenced in the post is a special case. It talks about a situation where people form a cached overly negative opinion, and apply it to a whole group. This makes them systematically wrong about the individuals of that group, who are not as negative as the stereotype, and thus this situation constitutes a bias, systematic error of judgment.
The post is poorly written, its topic or contribution are unclear.