John Stuart Bell proved such superluminal communication was not possible.
The article doesn't claim that superluminal communication (in the sense of relativity-violating information transfer) is taking place.
I read your link carefully. The only reason Mary can't get information faster than light is because the source in the middle emits paired electrons with a random setting. If the source only emits electron pairs that are green for position 1 and red for 2 and 3, then I can fix my detector to position 1, and Mary can set hers to position 2. If I turn my detector on, Mary will see 50/50 green/red. If I turn my detector off, she will see only red. Hence she can know whether my detector is on or off, which is information faster than the speed of light.
This doesn't violate locality or Einstein's information speed limit if the paired electrons share the same location while they appear to move away from each other. They both take their original location with them. This isn't communication over a distance, it's somehow sharing the same bit of universe location in what we incorrectly perceive as two distant locations.
It's a very interesting subject.