A critical difference being that Vader was visibly stomping them prior to that, whereas that isn't evident in Desann vs. Luke.
Of course it doesn't matter: Desann was empowered by the Valley of the Jedi when he went after Luke and Luke is an in-universe jobber of epic proportions.
When he "gets serious" {a phrase I use loosely}, he shitstomps the UnuThuls of the galaxy.