I don't understand the request. There are no "particular kinds" of colour blindness in play here; in context, the term refers to one clearly defined concept — i.e., not taking race into consideration when making decisions about how to treat people. That this is a core liberal value is so self-evident that I can't fathom why support would be necessary. But try considering it from the perspective of Rawls' Veil of Ignorance, for example.