How acceptable is it to publish an article without the author's knowledge?
It is obviously not ok to publish the work of someone else without asking all authors. It is also certainly startling to see it done in such an apparently careless manner (as an unedited copy of a thesis chapter that doesn’t conform to the standards of the publication journal - and still somehow gets published). So what happened is puzzling.
Realistically, there is nothing you could have done to prevent it from happening. Given how strange this story is, you couldn’t have been expected to explicitly tell your adviser to please not do what they did. Maybe they meant well, maybe they did it to add a publication to their own record, but they shouldn’t have done this as they did.
What this means to you depends on details you don’t mention in your question (e.g., are you in industry or academia, did you plan to use your thesis work in other ways, are you worried about what you consider a sub-par publication).