reason (added after poll finished):
A major reason for shipping them is how they often have similarities in their character arcs and their potential for cuteness or angst. Oscar and Ruby, in continuity, often serve to ground and reassure the other when one becomes worried or overwhelmed and are shown to get along well together, with Oscar eventually incorporating the color red into his outfit (an in universe sign of romantic affection). Actors and writers for the show have all shown approval of the ship in interviews, while subtextually, Oscar references the story of "the Little Prince" where the titular character is in love with a rose. Overall, Rosegarden is a wholesome enjoyable ship with a healthy fanbase and plenty of room to grow.