If while in level flight, you banked an airplane to the left 30degrees and added no up or down elevator and didn't add any power, would the plane still turn? Yes.
If you strictly just banked 30 degrees left, how is that changing the relative wind? For that split second you'd still have a parallel relative airflow going across the body of the airplane, then the forces imparted by the aircraft being banked 30 degrees would take over. The reduction of the vertical lift component would cause the nose to pitch down, then changing the relative airflow on the wings would cause a
slip to the left which would in turn change the relative airflow and would help "push the tail around", as well as the differences in the angle of attack of each wing would create more drag on the outside wing, yawing the aircraft slightly to the right, then the nose drop would increase the airspeed, increasing the overall lift and raising the nose again, etc. Depending on the stability built into the aircraft, it will be different from aircraft to aircraft. You should go try doing that in an airplane and then note what happens. TONS happens and this can't be a justification for the weathercocking because now the aircraft is in a slip.
RE: "push the tail around"... that's because it's in a slip and not in coordinated flight. In a coordinated turn I don't believe you're going to have weathercocking whatsoever as the relative airflow is parallel to the aircraft's longitudinal axis. Even in a 30kt wind, it's the same thing. It doesn't matter what the ground below you is doing, if that ball is centred, you're in coordinated flight. In a slip or skid you will get the weathercocking effect, which would return you to coordinated flight, but to stay in the slip or skid you're actually fighting the weathercocking tendency by using the rudder.