The cartoon takes the literal meaning of "colour" and therefore allows the speaker to like a society with black people and white people, but not (for example) red people and green people.
In the real world, colour-blindness is generally meant to indicate that a person is blind to the race of others. This is sometimes presented as a positive, but can actually be a problem. As Derald W. Sue from the Teachers College at Columbia University writes,
I have come to realize that color blindness uses "whiteness" as the default key and mimics the norms of fairness, justice, and equity by "whiting" out differences and perpetuating the belief in sameness and equality. The denial of power imbalance, unearned privilege, and racial discrimination is couched in the rhetoric of equal treatment and equal opportunity. The pretense of not seeing color is motivated by self deception. To be colorblind not only denies the central importance of racial differences in the psychological experience of minorities (racism and discrimination), but also allows the White person to deny how his or her whiteness intrudes upon the person of color.Read the rest of this short article online:
The Color Blind Society: Whiteness as the Default Standard