Read again. The point was that it should be a button that looks like a button, or a link with proper fallback for non-JS users. It should have a title attribute

Read again. The point was that it should be a button that looks like a button, or a link with proper fallback for non-JS users. It should have a title attribute and feedback as well, for screen readers. It should never be a button disguised as a link, however. Fake links are much worse than javascript:void(0), because they break expectations of users, and are more prone to breaking. At least with javascript:void(0) browsers are able to use it as a hint to disable certain context-menu items, and it's much better than having a fake link. For accessibility purposes, if you need button behavior but link-look you should use role="button".