A theory is (as Heisenberg explained in his book "Physics and Philosophy") an interpretation of data based upon unscientific, non-falsifiable, a priori assumptions on the part of the theorist. You can't really disprove something as nebulous as "hidden variables." That's not a falsifiable statement. What you can do is disprove some theory based on hidden variables. Such evidence does not apply to the possibility of other theories of hidden variables that are yet unformulated.