The DCL website is indicating that the Flexible Refund Policy allowing cancellation for any COVID-19 related reason is applicable only to cruises booked before December 9, 2022.
https://disneycruise.disney.go.com/faq/flexible-refund-policy/what-is-flexible-refund-policy
For cruises booked on or after December 9, 2022, passengers who test positive for COVID-19 within 10 days before sailing may cancel or reschedule without cancellation fees:
https://disneycruise.disney.go.com/faq/health-safety/covid-policy/
https://disneycruise.disney.go.com/faq/flexible-refund-policy/what-is-flexible-refund-policy
For cruises booked on or after December 9, 2022, passengers who test positive for COVID-19 within 10 days before sailing may cancel or reschedule without cancellation fees:
https://disneycruise.disney.go.com/faq/health-safety/covid-policy/