It's like that dumb question people love to ask: If you could go back in time and kill Hitler as an innocent baby to prevent the millions murdered later, would you? Most people answer "yes." Most people answer yes immediately.
So I buy it.
When I see people arguing against what they see as the mishandling of Luke in this movie, it always seems like selective memory.
Having a moment of weakness and making disappointing decisions when worried about future innocent deaths is completely in character for Luke. You talk about Luke throwing his lightsaber away in Jedi to uphold his convictions. Yes, that happened. You seem not to remember what happened immediately before that. Yes, he surrendered peacefully. Yes, he tried to sway his father without fighting.
BUT THEN
Vader mentions one word about Luke's sister and what happens? Luke instantly flies into a mindless, murderous berserker rage. He came a hair's breadth away from killing his dad and probably would have if the Emperor hadn't inadvertently snapped Luke out of it by continuing to needle him.
Their handling of Luke is the single thing this movie DID do right. I get that it's a disappointing moment for fans. It's supposed to be. People have disappointing moments in real life. And Luke has never been perfect. I don't get why fans think he should've suddenly been perfect now.
It is absolutely NOT the best way to handle Luke.
Luke has already BEEN down this road. His journey in the previous films has already taken him down this path and he's overcome this particular challenge and overcome this particular set of hurdles.
If they want me to believe Luke can fall down into this pit again, after everything they've already established with this character in the previous films and the fact that the character's entire arc evolved into overcoming the risk of turning to the Dark Side, they have to sell it to me. They didn't even try.
Rather than selective memory, I think you just really want to like this so you're finding reasons to do that.
Killing Hitler when he's a baby? Luke would not kill Hitler when he was a baby. Not after everything they established with his character in the previous films. He would work to keep him in the light because it's already been established that's how Luke would do this from the previous films.
They didn't sell this. They didn't do this properly at all. They fast tracked it and hotshotted it and its messy execution shows.
EDIT: You know, something else you said also bears a special comment:
BUT THEN
Vader mentions one word about Luke's sister and what happens? Luke instantly flies into a mindless, murderous berserker rage. He came a hair's breadth away from killing his dad and probably would have if the Emperor hadn't inadvertently snapped Luke out of it by continuing to needle him.
This is really not a very good argument.
Point One:
Vader mentions Luke's sister as a way to trigger his anger and continue the old struggle. Yes, Luke fails because at that moment, alone with his thoughts and fears as he struggles against Vader and the presence of the Emperor, he's back in that tree. He fails there and commits to using violence to solve the problem.
BUT THEN
When it matters most, he casts away his lightsaber, thus PROVING Luke has at last overcome his weaknesses. That is the moment when Luke matures beyond giving in to anger and fear. This arc is
done. Having Luke regress to pre-
Jedi form is a hard sell and unwise. If they're going to go down that road, it needs to be done better than it was done in
The Last Jedi.
Point Two:
When Luke
does break, it's
before he steps away from the precipice. When Yoda and Ben are speaking to Luke on Dagobah, the nature of the conversations are foreshadowing that his challenge is yet before him. It's not as if Luke had overcome all of his anxieties and fears
before confronting Vader and suddenly regressed. He hadn't completed that journey yet. He
couldn't have completed that journey yet because the movie is building towards that exact moment when he
finally breaches the gap.
So yeah...I have to dismiss your argument.