I dont think I can explain this to someone who likes Luffy.
I used to like Luffy, in pre-TS, when I was mostly a casual anime watcher.
But once you stop being a casual and see how much the story suffers because of him, you start to find him very annoying.
Not to speak about frozen world due to MC not being present and the incompetence of everyone, especially those who interact with MC. Tension doesnt exist with someone who has infinite chances that extend even through death...