"I'm not sure if the tag is just a joke or the name of a legitimate new style of composing music, but it's wonderful regardless. " Yah, it's a really good description of the aesthetic of this entire recent hipster thing honestly. I mean "hipster" doesn't describe anything, but what we know is people are wearing 1940s hairstyle and Tweeting on their iPhones at the same time.
I'm not into many of these artists, but my guess is that this is a way of describing modern electronic that goes for a nostalgic feel, maybe like the tones and synth of proto-electronic stuff (video game OSTs, Sci-Fi movie OSTs, perhaps disco, BBC Radiophonic Workshop) with the engineering and arrangement of a state of the art, modern production. I've got a lot of stuff that matches the description I've just given, but this is probably a small group of people's way of describing these trends.