Why "what the hell"? This is exactly what happened, and a logical consequence the moment IP addresses are classified as private data. Which it is in a system where it can be used to find the civil identity of the user, which is the case in Germany via Vorratsdatenspeicherung and the rampant misuse of the legal system.
Note how the decision contains the question of whether leaking the IP was necessary. They noted it is not necessary to serve the fonts via Google, it can happen without leaking the IP (I assume they mean self-hosting):
> Google Fonts kann durch die Beklagte auch genutzt werden, ohne dass beim Aufruf der Webseite eine Verbindung zu einem Google-Server hergestellt wird und eine Übertragung der IP-Adresse der Webseitennutzer an Google stattfindet.
translated:
> Google fonts can be used by the defendant in a different way, so that a connection to the website does not make a connection to the Google server, thus without transmitting the IP address of the website visitor to Google.
Which is good news! It is a totally consistent decision with the current privacy rules and best practices: Do not save or leak private data if not necessary, always minimize data exposure as much as possible. The as much as possible part is very important - if there is no way to embed Youtube videos without leaking the address, then that's still possible to do. Sounds fair to me.