Thank you for concurring with me. This is also the explanation i could come up with while observing food mixer blades(they resemble a fork more than a spoon), tough the flow is more turbulent in that case.
The whole point of the spoon or fork is to create turbulence. In a clear container, you can even see the turbulence created as the solute dissolves creating mirage (portions of the solution have different densities, refracting light differently), provided you stir slowly enough see it happening.
While i do understand that a larger surface area of the spoon will "flap" the liquid around better, but assuming similar motion with a fork might mean a more heterogeneous mix.
Of course we haven't mentioned the intensity of mixing. A food mixer's blades appear more closer to a fork than a spoon.