Not to mention, Ru'afo isn't necessarily a simple thug. Moving the Ba'ku to another planet without their knowledge, so they can die slowly while he enjoys the benefits of immortality strikes me as a pretty delicious (if complicated) revenge. I don't think he necessarily needed the Ba'ku to know he was the one who doomed them, just that they were doomed in the first place, and he would live on. Would he have simply used the collector to kill the Ba'ku if the Federation hadn't been involved? Possibly. But once they were involved and brought the holoship into the picture, I can see him being okay with the Ba'ku just dying "naturally," as long as he gets his Fountain of Youth.