This is "not allowing cross site at all" so, technically it's not "request forgery" protection. Yes, this is very semantic, but, CSRF is a vulnerability introduced by enabling CS and CORS. So, technically, same-site cookies are not "protection" against CSRF.
Cs and cors have nothing to do with csrf... Though, yes, neither does same-site
I don't understand your distinction at all. I may not quite grok your meaning here, but CORS is usually discussed in the context of allowing cross-origin AJAX calls.
But cross origin form posts are and have always been permitted, and are the main route by which CSRF vulnerabilities arise. Nothing on the client or server needs to be enabled to allow these form posts.
Furthermore, the approach detailed in the article simply has the server block requests if they are cross site/origin requests, so I'm not sure what the semantic difference is.