Racism may not have been the intention of his or her comment, but it can certainly be perceived as such. Also, if you say something like "I want to date my own race", what exactly to you expect people to think? It certainly implies some kind of dislike.Anyway, strictly relating to personal preferences I don't consider it racist to say "I want to date my own race/culture, and I like to hang around people of my own background".
Also, my co-worker's statement clearly indicates that he thinks black people are an "inferior" race, thus making it a racist and biggoted remark.