The nuance that's being made here is that the public cryptanalytic results we have are from researchers that need to publish. However blackhats (be it government or private) have no such need. Thus, they do not care if the analysis is elegant or neat.

This means that ARX functions will have less published analysis, but may still be successfully attacked.

This isn't even a new argument they're making here. It's been well understood that simple cipher designs are better, because they are easier to understand. If you can understand it well, yet not break it, that gives confidence. If you don't understand it, it might break as soon as you do.