This seems unreasonable, since he was presented with evidence that showed a strong correlation between more choices and fewer errors. In hindsight, this turned out to not be a causal relationship, but the CEO had no way of knowing that at the time.
If you started making decisions based solely on rational arguments and facts, would those lead to better decisions?
Almost all business are built on intangibles. Emotion, creativity, personality, feelings, loyalty, love etc. These intangibles are extremely difficult to explain yet most decision makers instinctively understand them.
The CEO probably made a decision on instinct. He was not rationally arguing the social integration, he instinctively denied its value. Rationally, you could probably prove the social buttons to be beneficial but you would have to disregard the intangibles.