I don't think it's meant to be taken that seriously. Just seemed to be saying that while in a lot of games skill can be inferred from how quickly a win is achieved, Civ is a Bizarroworld game where rushing is actually an easier win than waiting for the AI to stop churning wonders and conquering city-states willy-nilly and get down to the business of playing the game. Likewise, if you are going to conquer AI cities, playing on Deity counter-intuitively just results in an easier game by virtue of having a nice banquet.You have your view on fast wins but the strategies taught to new players to help them on harder levels were created by the fast players. Impressive or not it is how they like to play. Please respect peoples right to choice.
@Lily_Lancer is now playing online speed deity and says that is the best test, rightly or wrongly. 20 turns doing nothing is a bit weird as you can be dead in 20 turns so I cannot take such a suggestion seriously.
Unfortunately, it is a zero-sum situation, as delivering a satisfying narrative of building an empire is at odds with blasting through the game in as few turns as possible. If Civ delivers one experience well, then the other suffers. Of course, the end design commits to neither.
The point of cards like Rationalism might have been to reward tall players, but 10 is just too low a pop. If it's a card you always take, it's probably a card that needs to be reined in.
Of course, as has been said before, this is all a byproduct of "multiple paths to victory" that actually require not diversity but singular specialization.