The blog-post asserts causality is not violated, but the author contradicts it elsewhere by claiming the hypothetical system would grant other benefits like "zero latency" gaming, which in turn means arbitrary data (e.g. human decisions) can somehow travel back-and-forth faster than light.
Then FTL communication opens up an enormous can of causality-worms.
That's a point, and I let them expand their definition of causality to include a chain of events flowing in a reversed arrow of time. I think they hand-wave away all those worms with the precept that any attempt to cause a paradox or other inconsistency would fail in practice. But I'd love to hear some examples that come to mind of problems that crutch doesn't fix.
Then FTL communication opens up an enormous can of causality-worms.