From the Insight book:
Apostates often seek to make others their followers. (Ac 20:30; 2Pe 2:1, 3) Such ones willfully abandoning the Christian congregation thereby become part of the "antichrist." (1Jo 2:18, 19)
So to part company with a Christian denomination is to become an Antichrist?? But reading just a touch further in the passage from 1 John they cite, one discovers that is a complete lie:
"The man who denies that Jesus is the Christ -- he is the liar, he is Antichrist." (1 John 2:22). Verses 18 and 19 refer to men who had appeared as "rivals of Christ", clearly claiming they, not Jesus were the Christ. That's what made those men "rivals". That's why they were "antichrists".
If I discern that a religious denomination is misrepresenting scriptures, claiming to represent God and Christ when it makes a pattern of overstepping scripture and making up its own rules and doctrines, then attempting to punish for life those who dare to disagree, surely I am free to exit that denomination. But in the weird world of Watchtower, exiting that religion, deciding that those self-professed representatives of God are no such thing, makes me an antichrist. Which is kind of odd, because actually, I still believe in Christ.