The comment you replied to is surprised that they did use their own TLD, thinking they should stick with their classic ___domain on not their own TLD (google.com)

However, using their own .google TLD makes sense the closer I looked at this link after you brought my attention to it.

This appears to be a branded and hosted version of a third party learning platform that might be simpler to deliver a whitelabeled expereince.

The login experience (either to use your google credentials or create your own account) seems to be the confusing piece.

I would not be surprised if this is not a third party piece of software in which case the login screen makes sense.