According to my wife, I am an apostate simply by associating with you all. However, I have never been a Jehovah's Witness.
So let's see, does that make Jehovah's Witnesses apostate Baptists or apostate Catholics if anyone in their rank and file were former Baptists or Catholics?
As Simon said, it is just a word. A word that they load the meaning of to scare and control people.