I studied the order. https://www.federalregister.gov/documents/2020/09/04/2020-19654/temporary-halt-in-residential-evictions-to-prevent-the-further-spread-of-covid-19
The reasoning behind the order is that if a tenant is evicted and homeless there is likelihood of spreading covid-19. Therefore the ideal would be banning all eviction. It would not make sense just to ban eviction based on mortgage status. If so, the CDC order would be easily challenged in court for being arbitrary.
However, the CDC said if your income is higher than $99,000, they assume you are unlikely to be homeless even if evicted, so in their order they banned eviction for those tenants income less than $99,000. That's the only meaningful qualification.