The message of Luke appearing in projection form isn’t that “the Jedi are good, actually,” it’s that image is everything. The real Luke doesn’t matter, because the specter of younger, popular Luke is what people like. It’s all about deception and propaganda. The actual Jedi and the actual Luke sucked but they’re a noble lie.
I mean, that’s going a bit too far I think. The movie clearly at least tries to end on a positive note, emphasizing that Luke’s heroic actions on Crate (Krait?) served as inspiration for a potential new generation of Jedi, beginning with ordinary people all over the Galaxy, like the famous “Broom Boy”. Clearly, the ending was supposed to be uplifting and positive, promising that the Jedi would rise again - in some form or another.
I think this ending is stupid. It pretty much killed my interest in the Sequel Trilogy. The whole movie is mostly stupid. But I can at least discern that the director at least wanted the ending to be perceived as hopeful and positive, but also bittersweet, like the ending to Empire Strikes Back.
I guess I’ll amend what I said. It isn’t necessarily consciously trying to be dour and cynical or make the audience feel bad at the end, but it’s clear that that is the worldview that it’s coming from. It’s saying that the Jedi returning is ultimately a good thing, but for symbolic reasons, not because they are competent or that they were actually good in the past. Like I said, nothing Luke said was refuted in any way, and it was confirmed by Yoda. The legacy of the Jedi was failure. And not just prequel-era failure, failure dating back to the original Jedi temple that should be burned down. Yoda implies that Luke screwed up in some nebulous way because he didn’t “pass on what he learned” to his students, which was failure.
The uplifting, positive part is that Rey could start over because she was taught… something… and that the common ordinary people in the rebellion can use the Jedi as a rallying force, like you said. But if you critically examine that at all, it’s deeply cynical about what heroism is, and about the value of tradition or culture. Again, the Jedi and Luke are a noble lie. That’s not necessarily consciously what the intention was, and maybe that’s a mean way to put it for some people here, but that’s the literal text we have to work with, and the writer chose to write it that way.
The “broom boy” is only “famous” on this website of 15-30 people.