Why was Tao Fuxin expelled from the county public security bureau?

Because he has been promoted to be a member of the Municipal Bureau Party Committee and director of the Political Department.

Dismissal means that the organ that enjoys the right of appointment and removal according to law exempts public officials from their posts in accordance with the provisions of laws or systems.

It should be noted that dismissal only means that the dismissed person no longer holds the original post, which is generally not punitive, so this word will be used in the normal job transfer of public officials; Public officials who violate laws and regulations often use this word. Because they were not suitable for their original posts at that time, they either changed jobs or resumed their original posts, so "dismissal" is not what most people think of as "dismissal".