Some people took SO too competitively. They tried to be the first to answer your question (even if by a single sentence that would be edited to a longer answer later), but when they could not, they at least tried to get your question closed (presumably so that their competitors couldn't get points for answering it).

At some moment it just stopped making sense for me to ask questions on SO, because if you can google the answer then what's the point, but if you can't google the answer, then some angry competitive user is likely to close your question for some reason.

At some point they got ultra aggressive about "duplicate" questions.

Technology changes at a fast pace .. so new questions would get asked, and then closed by moderators and pointed to similar questions that might be 5 or 6 years old and no longer relevant.. essentially ending the discussion on many topics and actively preventing progress in certain areas.