At least in some countries authors get a compensation every time their book is borrowed from a library. So you might still be indirectly supporting the author when borrowing from a library. Also if there’s enough demand, the library may acquire additional copies and the prices for libraries are higher than for consumers.

https://equityatlas.org/how-do-authors-make-money-from-libraries/

Conversely, when you are borrowing a book from an author you like, you probably are supporting them and do not need obliged to purchase it for yourself.

You ask an LLM to code something and then just run the code blind without reading it and if it seems to work, publish the application. You can imagine how many performance and security problems it produces.