Many people here seem to forget that cookies aren't the only way to track, and fingerprinting a user is easy without having to use cookies (via UserAgent, IP, canvas data, and a myriad other techniques).

Now, I wonder what does the GDPR and similar legislation say about those, but my uneducated guess is that a user accepting the site's policy regarding user data collection would approve the use of fingerprinting as well (and deleting the cookies would only work partially, privacy-wise).