There's overlap in travelers who work festivals in the summer, dpw at burningman and spend some of the winter in slab city.
There's also digital nomads doing vanlife there.
Much of the art has a distinct BRC vibe. The founder of East Jesus was a burner in the art car scene. Last winter there was a giant LED penis up at one of the camps, and spaceport 42 is a collection of 6 burned out trailer chassis planted vertically in the ground.
I think the article under estimates how many people live there in winter, and over estimates how many people are there during the summer.
During the winter some camp will host a gathering usually an open mic most days of the week. Hanging out around a camp fire listening to songs one time I commented to my neighbor how I've never heard so many songs about a place before. He said, 'no song writer comes to slab city and doesn't write a song about slab city.