...by people who don't know what really makes a bike fast or slow.

The weight difference of perhaps 1 lb. will have limited benefit to climbing. Inertial differences and the slight benefit to acceleration is even more limited (true hair splitting stuff).

Aero differences are a little more significant than the above, but you don't have to spend huge dollars to get reasonably fast wheels. Factory wheels with low spoke counts and a tire width that mates to the rim width will get you most of the way there for cheap.

Want to go fast, get your position on the bike aero, don't wear flappy clothing, use low Crr tires, and yeah, get some reasonably aero wheels. Oh, and train hard.