Doesn't it come down to the lack of an equal opposite force, or basic physical dynamics? The water hitting the bottom of the sink is coming with a certain force, then it hits an immovable object--the bottom of the sink, and spreads out. As the water continues downward from the tap, the force is a constant. The water trying to get inside the circle is not coming with any where near as much force.
Please allow me to illustrate with my toilet bowl. When I can't get everything to go down by flushing alone, I have to use a bucket of water, adding force due to the weight of the water in the bucket as well as the distance the water is coming, picking up speed due to gravity. If I were to flush it at the same time, the water from the bucket still pushes all the other water up and out before coming back down and going down the hole first. Then, the flushing water goes down.
Ultimately, I think it has more to do with fluid dynamics and the nature of the water, which perhaps the physicists aren't taking into account.