When you say plagiarizes, do you mean they are publishing their own docs without ads? Or you mean when the AI is reading the docs instead of a person they ignore the ads?
The test for writing a book is whether the author applied their own judgement in the creation of the book. Even if some explanations of concepts are inevitably similar the structure of the book, the example code, etc. will reflect the author's judgement and experience.
An LLM is incapable of authorial intent. It's not synthesizing the docs with a career of experience and the input of an editor. It's playing madlibs with the work of one or more prior authors.