I get that this might annoy you, but there is a direct trace all the way back to the original Mac in 1984 that required a mouse. As time went on and the two other OSes we still have gained mouse support (Windows, Linux) from their keyboard roots, they brought forward their ethos of keyboard navigation. Mac OS resolutely stayed attached to its mouse only roots.
That seems incredibly subjective. For people with carpal tunnel like myself, having to do everything on the keyboard can be very painful. The mouse alleviates that and gives visual feedback.
