Dr. G, it's nice to see you. We should get some bourbon together. I'm in Anaheim all the time.
You're correct, if you assume that Luke is a white knight hero. But he's not. And the evidence is strewn through the whole saga from IV on.
He failed in his rescue of the princess in IV, he failed in the cave in V, he failed to rescue Han in Bespin again in V, he failed at Jabba's palace in VI, he failed in his challenge before the Emperor in VI,...and like Yoda said in V, "
If you end your training now? if you choose the quick and easy path as Vader did? you will become an agent of evil." Yoda is never wrong. And sure enough, Luke even admitted his failure to Kylo, in VIII.
He's a 1/2 assed Jedi who had to tuck tail after his fathers death, because he realized his whole life is a failure. Hence his cynicism in VIII, and his mantra that the Jedi should end. (they really don't have that good of a track record of maintaining peace in the galaxy).
It's a profound character study of what it takes to take ownership of when you're wrong. No wonder the rebellion has lost it's way.