Anyway, one of their arguments is that in such a widspread galaxy, it is still only humans that aid the Rebellion. Not until ROTJ do we se any alien members at all (besides Chewbacca).
Obviously, the real reason was effects and coustume limitations, but they try to paint the rebellion as rascists. My point is that, with the Rebellion growing in strenght after the massacre of Alderaan, perhaps we should se an alien or two among the rebels?
Unless this is too hard to do, of course, but it would be nice to undermine those kinds of threads further.