• Почему после all как правило употребляется the (all the people, all the stories)? Что за правило?

  • Обычное, на употребление определенного артикля.
    Ну почему, бывает и такое:
    All with no article
    When all refers to a whole class of people or things, we don’t use the:

    All children love stories. (i.e. every child in the world)

    Not: All the children love stories.

    We don’t use the with time expressions such as all day, all night, week, all year, all summer:

    I spent all day looking for my car keys.

    The party went on all night and some of the neighbours complained.