In one of my discussion groups, one man mentioned that his union rep was a Japanese-American woman. She began to give this man the "person of color" speech - then immediately dropped her head with the painful memory of other persons of color - Blacks - that beat her up a few times on the bus ride home from school.

The inaccuracies aside, using terms like persons of color suggests a racist us-against-them attitude, where there is White people and everyone else. My own experience of working in a multi-racial office was there were significant differences between different races and ethnicities - and that each group preferred to only associate with members of their same group.
Oh - and White people only made up 25% of the staff,