Wat
Paradies were the absolute underdogs, no power at all. Until Eren revered things by sacrificing everything and counterattacking. And in his case, he KNEW that the outside world would attack again if he didn't eradicate them; the post-credit scene proved him correct, btw..
Meanwhile Rimuru is the one in power here, at any given point. Worst case, he puts up a defense wall and keeps negotiating until humans grow tired. And he could have killed just individual, strong and evil soldiers to show the others how powerless they are against him. You think the 100k soldiers would have keep attacking the monster village had Rimuru given them a chance to realize how weak they are?
Rimuru is a tyran, Eren was a savior.