This drawing illustrates the wind conditions required to accomodate a common misconception among roofers (and promoted by a ridge vent manufacturer) regarding the supposed " short circuit " of an attic ventilation system.  

For a "short circuit " between ridge vent and gable vent to occur, the wind flowing past a house must only act on, or flow over, the ridge vent at the peak of the house. The low pressure created at the ridge of the house would then draw air from any other opening/vent in the attic space.

Obviously, the wind does not act in the manner shown.

This drawing illustrates the actual wind flow around a simple gabled house, although simplified and in only one direction. 

As air pushes against the windward side of the house, it creates positive pressure and pushes air up and into the soffit vents. Pressurizing the attic.

As air flows around the house it compresses and increases velocity. This creates the low pressure that pulls air from the attic openings, whether ridge, static, or gable end, in the roof or walls.

In actual real world conditions, the wind will come from different directions, and affect the attic vents in different ways. Either pushing or pulling air out of the attic space.