According to the USVI travel portal:

Every traveler aged five or older who enters the U.S. Virgin Islands by air or sea, including anyone in-transit to another destination, is required to use the USVI Travel Screening Portal and receive travel clearance (email with green QR code) before travel to the Territory.

Confusion could be that there is an initial pop up on the portal site that says IF you are fully vaccinated in the USVI, and IF they can verify the vaccination in the Department of Health database, and IF you are traveling from the continental US to the USVI, you MAY be eligible for an exemption to the requirement of testing negative - something along those lines.

Guessing it doesn't apply to most of us here. Plan on getting the test!