I'm always wanting to say something like "Sburb was doing some Little Lord Fauntleroy shit to Dirk Strider," but I forget that not everyone has read Pink and Blue: Telling the Girls from the Boys in America, and so probably don't understand what I mean by that. Actually just now I found a Substack article by the author going over what I think was most of that section of the book, check it out of you feel like it.
But like basically the gist of it is that the prince godtier outfit infantilizes Dirk in a way that simultaneously affirms his maleness, but makes him feminine in the way that children are considered feminine. It's very in keeping with all the ironic "plucky youngster" language used all over Homestuck which is a nod to the cultural fetishization of childhood that adolescents begin to feel a nagging discomfort with once they become more self aware.