It hides them, but also blocks most of the trackers anyway. Compliant websites should not track you before you consent. If they don’t honour this basic GDPR rule, it probably won’t honour your choices either.
I'm not a lawyer and I think you're right about the website's responsibility. It might be a bit more murky to assess whether the user agent is abusing the website (OMG, piracy!) if it looks beyond the modal cookie pop-up bypassing the actual choice. I mean, along the lines of skipping the mandatory DVD banner that says "the FBI will come after you if you copy this movie or skip this banner", DCMA style.
But yeah, that's probably just a nitpick only paranoid IP lawyers might consider pursuing.
(Not sure if this actually matters in practice, but I'm sure lawyers would have ideas about what one or the other implies legally...)