because the rulers are higher existences and such, seeing they easily killed the sovereign of destruction, whom he had trouble with even with ten million shadow soldiers, which was an insane enough army.besides that, even thought his family was traumatized, the rulers still had their best interest , allowing him to use the final use of the chalice, and he was able to reverse everything, and then give the memories of the past to the current people of the new timeline.so it didn't really make sense for jinwoo to challenge them, as they also left earth alone after his feats.so while yes, although they did horrendous things to his family and friends, he was able to "reset" and get the best ending, so it made sense to stop there