The specified reports API allows only Reports.Read.All permission. The Reports.Read.All scope requires admin consent, so only Global Administrators can consent the application, which leverages the reporting API.
So the application can't be consented/accessed by users except for global admin, then why there is a requirement for the signed-in user should have the list of specified roles?
My guess it that this is tied in to the incoming changes with respect to "lessening" the requirements for consenting to certain permissions, etc. You can always use the button on the message center post to send feedback/request clarification, or to the same on the docs.com article - better chances for someone from Microsoft to see it.