They can stall in theory, unless a new rule is introduced, because the idea is the MC to get someone as lover, so if they just "friendzone" him rule 11 and 12 wont work and to put on a harem game terms he will reach the "remain single ending".
Everyone had the same points so unless the game had some special rule as long as they didnt participate but didnt make him hate them theres no problem. And killing them all would be counterproductive because there would be no point on the game then. Its just a failsafe in case they refuse to play the game but on this case they would playing the game but not on the intended form due to a rule loophole