Why is the US Space Force researching 'orbital warehouses'?

The U.S. military is looking into putting "orbital warehouses" into orbit around Earth where fuel and other materials could be stored for easy pickup by future spacecraft on satellite servicing missions. A new U.S. military challenge aims to "accelerate operational logistics" for to help the U.S. Space Force keep its satellites active and respond in a timely fashion to threats. The challenge was created amid repeated warnings that China and Russia are actively maneuvering their own satellites close to U.S. spacecraft in orbit and launching new types of orbital weaponry. More

(Source: Space.com - Jun 14)