If fully colorblind people only see shades of white,gray, and black, does that mean that the colors black, white, gray are colors humans can’t see?
Based on your question: if fully color-blind people see whites, blacks, and greys, that means that humans can see them colors. After all, aren't color-blind people humans?

If you actually think about it, is color just created by evolved cells? If so, should we not see just black, grey, and white?