They took it after winning 1st sino japanese war. If there was no1 there. Why didn't they take it earlier. You don't sound right just because you're a female BE ret pally making insults; you sound right with quoted evidence, which you havn't provided any. If this was a classroom, would you be so aggressive?
From the larger standpoint, it would be better for American interest to let Japan have the islands. China's hold on the western pacific would be weakened.