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.
Or not.
I mean there is nothing to indicate that this is Luke’s intention. And does Vader really look like he’s in the mood for a bitchin’ team-up at that point? I think this whole “Luke planned it this way” thing is a real stretch.
It’s also not in the novelisation. There’s no 'Luke threw his Lightsaber aside, hoping in that moment that Vader would see the light and help him rid the universe of this Emperor". No, Luke stumbles through it all just like it appears in the film, with the one caveat being that he does actually hope to kill the Emperor at first but realises - at the time that he ditches the saber - that he can’t give in to violence. Nothing about a masterplan or believing Vader would turn.