The reason they buried Rufus is because Rufus identified as Jewish and as part of Jewish law, you are not supposed to be cremated (or tattooed). So they respected his wishes and buried him. Plus after Rufus died, I don’t think he had any official unfinished business so I think it was ok that he was buried. Hope this answers your question.
I fucking love the character that’s like. not really the villain. but definitely not a good guy I mean he’s on our side. but he’s definitely not morally upstanding.