That is the exact opposite off what it says. The US government has actually mandated IPV6 only networks in the next few years.

>At least 20% of IP-enabled assets on Federal networks are IPv6-only by the end of FY 2023;9 >b. At least 50% of IP-enabled assets on Federal networks are IPv6-only by the end of FY 2024; >c. At least 80% of IP-enabled assets on Federal networks are IPv6-only by the end of FY 2025

https://www.cio.gov/assets/resources/internet-protocol-versi...