The website has no relation with the law, and is not an authoritative source of information. It's not even a particularly good one. It's just a website run by some guys.

Cookies per se have nothing to do with the GDPR. In fact, if your cookie is not tied to a natural person, the GDPR does not even apply. Also, cookies are under your control. You can alter and delete them whenever you want.

As an example: If your site allows different styles or languages and you want to store the setting in a cookie, you do not have to care about the GDPR. Only when you track your user's behavior with a cookie, the cookie banner thing becomes relevant.