I see no reason for claiming a fluid in contact must exert a force in any particular direction.
surely by the definition of pressure, it exerts a force in all directions.
The wings in the tunnel are
deflecting air downwards, I don't dispute that but the amount of downwash is very small - even at high AoA the streamlines even a short way below the wing get closer together but no more so than those a short way above it. How can you emphasise the downwash and ignore the upwash?
Strange how everyone is such an instant expert in this field.