It seems like a lot of y'all liked it, and it felt pretty reactionary to me so I'd love to hear an alternative perspective.
Beyond the idea that it's a film about imperial colonial extraction from which we only get the perspective of the empire, it really feels like the presentation of the lifestyle of the royals seems very sycophantic, very deferential.
Like the royals don't experience lavish personal consumption or luxury, no sex slaves, no hedonism, no fun at all really, they're all just earnest and stoic hard workers. The representation of the ruling class is that maybe your bedroom might be a little bigger, but they're just as put upon as the rest of us because of all this duty they're so concerned with. It seems like the take-home message is that any material benefit of being in the ruling class is trivial, but the accompanying responsibly is a terrible burden.
(I haven't read the books and don't plan to btw.)
So can someone explain why they liked it as a leftist?
You didn't get the part where Paul is the tired white savior archetype? Who civilizes the savages and uses them for his own ends?
No it's subtler than that. Paul is the critique of that stereotype, since he ends his journey broken, alone, blind in the desert having lessened a people and unleashed genocide upon the galaxy. It's pretty explicit that the white savior trope is bad and only ends in evil, destroying both the savior and the once great people he used towards his own sick ends.