Shanghai University is centralized and isolated. Why do many people live in the same room?

Because isolation depends on the configuration of the room and the number of people being isolated.

If the same disease is diagnosed, they will be placed in the same room for isolation. Maybe several people live together, because there are not so many single rooms in schools and hospitals.

There is no special specification for this. The number of isolated personnel and the configuration of rooms may not necessarily ensure the normal life and daily life of isolated personnel, but may also be one room for each person.