I think it's probably better to simply say that "authoritarian" is a buzzword, though your implied argument that all states work by exerting authority on (at least some portion of) their population is certainly true. Anyone who uses a term like "authoritarian" rather than even a marginally more-descriptive negative term like, idk, "bureaucratic" or "state capitalist" (which gets misused, but I digress) is immediately demonstrating themselves to have untrustworthy judgement on the topic

Hot take. What's the eli5 behind the idea?

Authoritarianism was a bullshit term invented by child-fucker libertarians to frame themselves as being the good guys.