"One Nigeria" is a phrase said out of convenience than what needs to be taken seriously. A certain person was quoted as saying "to thine self be true". Speaking generally, we know that we don't believe in the oneness of Nigeria. You can't make friends with someone because of his tribe. Landlord won't accommodate because of same. Yet we are quick to form solidarity when a black man falls victim of the high - handedness of a white.
See a screen grab of the conversation between an estate agent and a proposed client. We aren't United.
To thine self be true!