Not that he's wrong about open-source abandonware, but that's rather an overstatement. No significant amount of his code remains in any modern browser, and when the engine that eventually became WebKit and later Blink (and which now powers the majority of end-user web client browsing today) was first announced as based off KHTML and not Mozilla tech, he wrote a self-congratulatory blog post[0] that started off with "Summary: I was right", even though it had nothing to do with him or his work. Not to mention KHTML was done using C++, something he was always against (no mention of "I was right" on that part, I see). He's done some good work here and there but he really gets carried away with his blowhard opinionating at times, and I think people should turn a more critical eye towards that sort of thing.
[0] https://www.jwz.org/blog/2003/01/more-khtml/