Huh? If anything, the Celtics were the least racist teams of the day. They had such great honky players in the 60s as Bill Russell, Tom Sanders, Sam Jones and K.C. Jones. One thing about Red Auerbach, he didn't care if you were black, white, red, green, whatever. If you could play his brand of basketball, he wanted you on the Celtics.
An amazing feat, considering the racial tenor of Boston in those days...
Which explains why even when the Celtics were winning those titles, the Bruins were more popular amongst Boston whites.