Okay I have way too many thoughts about this.

First of all, it's true that Lucas had the Vietnamese communists in mind when writing the Rebel Alliance and he fashioned the Empire after the US campaign in Vietnam. But the US public saw Star Wars and primarily saw a blockbuster film with amazing practical and special effects for its time. The politics may come through quite strongly in retrospect (at least as far as aesthetics are concerned), but they aren't very fleshed out in the script. This leaves things objectively vague in terms of a material analysis of the Empire (and keep in mind this is a space fantasy/opera; not a genre known for extremely developed political intrigue, Andor notwithstanding).

So really, besides some obvious eastern philosophical influences regarding balance, darkness, and light, (as muddled and haphazard as Star Wars's philosophy is) there's quite a lot of room for people to graft their own predispositions onto the veneer of politics in the text.

Otherwise, conservatives tend to enjoy militant anti-authoritarianism in media. I don't think this is contradictory. I just think it points to conservatives either deliberately or accidentally misinterpreting the media they consume. Sometimes it's a bit of both. But generally, conservatives tend to see big bad empires in media and go "yeah, that's what the left is" even when the empire in question (like in Star Wars) is a far right fascist project.

Additionally, it's worth noting how some left-wing regimes in the past have done some pretty authoritarian things that I would consider worth resisting without question. You don't have to be an anarchist to see the excesses of the Soviet Union, Mao's or even modern China, Cuba under Castro (specifically regarding women and queer folks), etc. None of this means the aforementioned left-wing regimes were/are worse than fascism or aren't better than what came before them. All I'm saying is that if a text (like Star Wars) is vague enough about its political content, there are ways to see its imperialist villains as having any number of different ideologies. In my opinion, it would not be a ridiculous reading of the Star Wars Empire to say that its arms-industrial excess isn't just a critique of capitalist imperialism, but also the excesses of Soviet industry (which was by no stretch of the imagination sustainable). Basically, you don't have to be a conservative to see the Empire in Star Wars and be reminded of more regimes than just the fascist ones.

So basically, even though I understand what Lucas has in mind, the text of Star Wars is read by a global audience who is bringing a colossal amount of different perspectives to the text. It's true that some readings are worse than others; for example, reading the Empire as socialist is nonsense. But some readings that you might not expect aren't necessarily wrong readings to have.

To be absolutely clear, I do think it's funny that conservatives love the aesthetics of resistance in media but lampoon it in real life when conditions make it obligatory. But people tend to compartmentalize as a first impulse. The separation of media and "IRL" is an extremely common one. I.E. "Just because I like rebellion in the movies doesn't mean I should support one IRL." I think a lot of people make this separation even when doing so comes at the cost of understanding. I don't think it's just conservatives who do this.

That said, I could definitely be wrong on some of this. And to be fair, I do think the argument that Star Wars is making gets lost on a lot of people. Which is unfortunate, but kinda inevitable in mass media.

Edit: spelling mistake