Another take on why "everything else is ignored" is because there literally isn't enough players. A 1x1 RP has only two people - perfect for a romance story. If you check the non-romance 1x1s (such as fandoms or historical retellings) they sometimes come with the requirement that players need to take on more than one role. I for one, am able to take on multiple roles, but many RPers can't (or at least don't want to).