When John reads Romeo and Juliet, why does Helmholtz find it so confusing and makes him angry?

Helmholtz cannot handle the intense emotions that come with the play. He listens to the section when Juliet is threatened to be cast out by her parents. This angers Helmholtz. He cannot reconcile these intense and conflicting emotions with his very sheltered and controlled emotional experiences.

The mother and father (grotesque obscenity) forcing the daughter to have some one she didn't want! And the idiotic girl not saying that she was having some one else whom (for the moment, at any rate) she preferred! In its smutty absurdity the situation was irresistibly comical.