Apostacy as described in the Bible is denying that Christ came in the flesh & was the Son of God.
Apostacy as defined by the WBTS is disagreeing with anything they say.
If we went by JW rules, Paul would be labled an apostate for disagreeing with the Jerusalem group over the issue of circumsizing gentiles. How dare he!
JWs are soooooo screwed up. Its best to ignore thier silliness.