I agree completely. In fact, I am, myself, color-anomalous; I see all the ishihara plates that "normals" see, and those that "color-blind" see. Learning color is absolutely another example of learning from those who have no access to your private experience.
Note that, in learning color, we do have a publicly available referent, which is easily agreed upon. Even though you and I do not know, and cannot know, that our experience is the same, we both label the same things "red" or "green" or "shade 1426 in this booklet". We literally cannot know what our perceptions are, and so the only thing we can agree on is that we, behaviorally, label this particular thing "red". Our own personal, subjective experience, is more accurately described by this external thing. It is, after all, how we learned to label our internal experience. Because of this, "red" is the public thing that we all agree to call red, whether or not it is the exact same for you and me.
Same with "consciousness". Quite literally, the thing we call consciousness is better described by the public, behavioral referents. We have nothing else. If it behaves as if it is conscious in every way, it is conscious. If everybody agrees that this sign appears red, it is red. By every measure we have available--even to ourselves--the public referent is the meaning of "red". Anything beyond that is idle speculation, and cannot even in principle be investigated.
