It's still modulation, modulation creates sidebands, and sidebands require bandwidth.
Nothing has changed, the Shannon–Hartley theorem still rules.
It's not modulation, it's multiplexing using a constant angular momentum. Modulation requires a change in something. With this case the they are sending seperate radio streams using different but constant rotated angluar momentums.
Think of it like 3D glasses in movie cinema that use right and left hand polarised light.