The headline is not wrong, its intentionally worded that way to mellow down the message. Its for the people who use their own custom domains to send emails via google without paying for the workspace by verifying the domain ownership (its a extra cost that google bears now for free). The @yahoo.com or @outlook.com are just to give a face to what other custom domains look like.

The whole point is if you have custom domains then pay for the google workspace if you still want to use it. Couldnt find it right away, from what I recollect it used to be $6 or $8 per email address