The sharing with ruters etc. is required to operate the service (website). Using a Google CDN for fonts isn't (required for operating a website).

The ruling explicitly points that out.

Furthermore DNS is handled by the contract you signed with you ISP or you explicitly changing it. Same for some other parts.

Where is exactly is the line for needed for operating a website and being optional?

What if you create your website in wix.com, the data from your domain will be shared with them AND it is needed for this data to be shared for operating the website.

EDIT: To make it clear, I always recommend self-hosting fonts and agree that Google CDN fonts should be avoided. But even if you self-host the fonts, those are still hosted on a server that is very unlikely to be your basement.