Does anybody see how the red lines in the "Strive for Quality, not Quantity" diagrams were generated? Looking at the data I don't get the impression that either

Does anybody see how the red lines in the "Strive for Quality, not Quantity" diagrams were generated? Looking at the data I don't get the impression that either one looks like it follows the data. Both lines seem to be as good as the other one in either diagram. I'm no expert but from having so many dots on the left sides and nearly none on the right sides I'd say the data is inconclusive. What do the data analysts say?