This article is about exported documents, i.e. the point at which you say "I am leaving the ecosystem of my chosen tool".

The wording of the interstitial page says "If you do not want to visit that page..." i.e. it's about whether you expected to visit one website or another. Surely google.com is as 'surprising' to the user as any other page.

BTW keyhole.com is an old Google-owned domain. From https://infogalactic.com/info/List_of_Google_domains

EDIT:

From my own experiment exporting a docuemnt it renders links as

https://www.google.com/url?q=https://example.com&sa=D&source...

I changed some param values, I don't know what they do. But with the original values it remembered my preference. So it seems like they're tracking and storing clicks.