Listen I don't want to argue just read this paragraph from the undertale wiki. "While initially cast in a sympathetic light, Asriel admits at the end of the True Pacifist Route that Chara "...wasn't really the greatest person." Asriel states that Chara climbed Mount Ebott for an unhappy reason, and adds that Chara "hated humanity".
At the end of the Genocide Route, Chara behaves in a polite, deliberate manner, thanking the protagonist for guiding them, and teaching them that power was the reason they awoke. They tell them that their determination woke them from death when entering the Underground. However, if the protagonist refuses to destroy the world, Chara becomes frustrated and confused, wonders what the player wants instead, and then finally gives in to the frustration, erasing the world anyway." -undertale wiki's Chara page