Just throwing his weapon aside and saying “ha ha you can’t make me angry” might be a nice piece of Zen, but it’s completely useless as a means to defeat evil and is of no value whatsoever to the thousands being slaughtered outside.
You’ve missed the point. It was Luke flipping the tables.
He was goading the Emperor to attack, just as the Emperor had been doing to him, believing that when he did, his father would return & kill the Emperor.
And it worked.