Your idea of how humans use content under copyright is mistaken.
I want to make an ajax request using jQuery. I look up an example in StackOverflow. I use a very similar code to the example given in the post and by not giving any attribution I just claim ownership.
Same with Spring in action books or looking up Java class references. Many times I look something up and use it as reference just tweaking the examples given.
Millions of programmers have done this.
LLMS in principle use the training data to generate an answer to the prompt, similar to the process I described.