I contributed a lot to StackOverflow in the early years. Most of the questions were interesting and not answered before. I almost stopped contributing in recent years because now there are so many trivial questions and questions that have been answered before. I see no value in explaining how to sort a list of peaches when there is already a question answering how to sort apples and one how to sort oranges. And I never understood StackOverflow as having the goal to teach programming but to help solving non-trivial problems. Now there seems to be a ton of question like how do I open a file in Python. More and more people seem to just ask everything on StackOverflow instead of reading a manual, a book, a tutorial or at least look if there is already an answer that can be adapted to their problem.
I can not quantify this, it is only my personal understanding of what questions should be on StackOverflow and what should better be looked up elsewhere, but I can to some extend understand that people get annoyed be some questions.