Why should I make up the room price difference when I live alone with a group tour?

Because the accommodation in the tour fee is charged according to the standard of double standard rooms, the accommodation in the tour fee you pay actually accounts for only half of the hotel room fee, and the other half is paid by the person who lives with you. Therefore, when there are single men and women, the travel society requires you to pay for the room. If there are other single people in the group who are willing to share the rent with you, you don't have to make up the difference.