The end result is that the fact that you visited this website is passed to Google, and this can then be used for advertising purposes.
Can it? Is this within the range what Google is allowed to do in the EU right now?
Because, if that is the case and we also wanted to stop that, wouldn't it be a lot more reasonable to just... forbid Google from doing that, instead of slapping every confused wordpress hack in the EU with a fine?
It doesn't matter what the promise.
They could sell their software stack to an independent European partner over whom they don't have any control and who doesn't transmit data back to the US.
Google's current GDPR consent screen is not compliant. It provides an easy "accept" option but no easy decline option, which is against the regulation.
Given they are already breaking the law and successfully getting away with it (otherwise they'd stop), why would they not break it here?
In fact, it doesn't even have to be malicious; the data can accidentally be fed into a dataset that's used for ad targeting - maybe it was set up that way a decade ago, nobody knows about it and it isn't entirely obvious considering the entire targeting machine is a black box with thousands of parameters so it's impossible to definitely prove what data was used to target a particular ad.
But if the website uses a URL that is unique for that site, or even for each user, that is absolutely something I'd hold the website owner responsible for.
Though I don’t think that Google Fonts URLs contain individualized parameters by default that disclose either the user’s IP address or the site visited. The ruling also does not mention that this is what happened here. All the site user did, from what I can see, is embed a Google Font.
Had the site owner put an automatic JavaScript redirect to Google on his page, he’d be just as liable, according to the logic of this ruling.