His point is that an aero frame won't endow you with "savage speed". From the aero section: "The latest evolution of the (Cervelo S5) species is spectacular in terms of raw aggression and savage speed.". Even accounting for hyberbole and that it's a "review" quote, the marketing here is over the top and at the very least misrepresented.

That's just one sample and not an unusual one. If you generally consider that "slow" riders are often the most inexperienced ones, for them this marketing is a sham or outright lie. Very small advantages are useful for very specific purposes and situations, even when those advantages are mathematically proportionally the same in other situations. Such as riding to the store for a coke at 12 mph. You may get the benefit, but to the same practical purpose as instantly responding to a surge at 28 mph to hold a wheel? Savage speed for a couple of seconds on that cola quest? The utility is not as they present it.