It's optional under certain conditions but those conditions are given as you correctly point out in the link to the HTML standard. While many seem to be focused

It's optional under certain conditions but those conditions are given as you correctly point out in the link to the HTML standard. While many seem to be focused on what Google says, it's nothing that those of us who read the actual spec didn't already know. And every web developer references the spec when they have questions...don't they?