Why does hamlet make gertrude choose between himself and claudius?

Through almost the entire play Gertrude chooses her husband over her son, therefore choosing politics over her domestic life. Hamlet loves his mother, but he resents her for marrying so quickly, and for marrying his fathers brother (this was a political move for both Gertrude and Claudius). Many times over in the play Hamlet refers Gertrude and Claudius' relationship as uous. He also refers to hell and heaven a lot, as well as using the sun and clouds as metaphor, 'I am much too in the sun'. I don't think he made his mother choose, in the end she chose herself. Throughout the play she refers to Hamlet as her and Claudius' son, but towards the end she says 'my son'. In the end she chooses her domestic situation over the political, arguably her last act of drinking poison was done on purpose so that Claudius held less power politically, though there are many different theories.