It’s fair to point out the big difference in parsing philosophy between HTML 2–4 and HTML 5, but what I’m talking about happened before HTML5 as well. Some people can’t handle the fact that HTML intentionally has implied elements.
> <!DOCTYPE html><title>Hello</title>" is fully standards compliant now
Sure, but switch the doctype and put a <p> on the end, and it’s fully standards compliant HTML 4.01 Strict too. And yet so many people are adamant that it can’t be. That it’s invalid (even though a validator says it’s valid). That it’s relying on error handling (even though the spec. says otherwise). That some browsers parse it wrong (but they can never name one). That the DOM ends up broken (when browser dev tools show a normal DOM). That you need <html> and <body> elements (even though it already has both). That there’s something wrong with it at a technical level (even though they cannot describe what).
The concept “This is correct HTML that works everywhere with no error handling” is very difficult for some people to grasp, to a genuinely surprising degree.