They were probably trying to portray the DFing as having taken place many years ago, back when they used the old-style announcement.
It is possible that they say "disfellowshipped" simply to make the point clear to the audience which might include many non-JWs. It is my understanding that the current announcement ('no longer one of JWs') is for legal reasons.
This was one of my beefs with the WT. They want everyone to accept the pain involved with DFing, but they themselves use language that protects themselves. They are so two-faced in every last thing they do. (Mt 23:4)
Bobcat