Sorta? The thread was about how odd it is that <div> has implicit end tags?
So, makes sense that the topic seems different, but it is the explanation for why a div grows to contain everything under it. For example, this is needed to know why the div in the following text closes.
Right? I get that the original confusion is thinking you can make a self closing div. But the fact that it expands to cover things that come after it requires you to know about the implicit closing. Hard to understand one without understanding the other.
Edit: I suppose it would be better for me to say that none of the examples on the immediate parent post are different, because none of them close the div? It isn't that the one div expands to cover everything after it, is that nothing caused it to be closed. Indeed, if those are just snippets from a document, you can't be sure that stuff that comes after it is also not included in the div.