The word "witch" means women are scary
I am as amused as everyone else at Jerry Falwell calling NOW the National Organization of Witches. It is sad that he thinks that's thigh-slappingly hee-la-ree-us, but I honestly don't think that the sheer humor value of it is why he chose the word "witch". Flea thinks that he was invoking a thinly veiled threat of death to feminists, and she has a point. But mostly I think that it's just Falwell's paranoia showing its face again. By saying that, he was making it clear that he thinks women are a force of evil and that's why they need to be contained.
Paranoid accusations that an oppressed group is really quite powerful and out to get their oppressors are as old as humanity. The favorite version of this in our society is the paranoid fear of black people that is common to white surburbanites.
Is this mental trick just excuse-making? Get them before they get you? Or is it projection?
I favor the latter theory, after examining all the instances of this you see in the modern day right wing movement. The more committed that a wingnut is to a certain kind of oppression, the more likely he/she is to attribute a similiar kind of villany to the oppressed group. Falwell is dedicated to restoring the patriarchy and he draws on supernatural authority (God) for his arguments. Of course he's likely to see women, and especially feminists, as a scheming mass of sorceresses drawing on supernatural powers in order to hurt men.
Arguing from projection is one of the favored methods of the social conservatives. Is your wingnut committed to banning gays and lesbians from obtaining legal protection for their families through marriage? Then that wingnut will accuse gays and lesbians of wanting to destroy marriage. Does your wingnut want the law to assist him/her in telling you what you can watch on TV or buy at Best Buy? Then that wingnut will accuse you of trying to sneak these materials into their home. Is your wingnut a member of a church that emphasizes witnessing and recruiting? You're likely to find a wingnut then who insists that gays recruit. It's even gotten to the point where a favored argument of those who wish to take away a woman's right to abortion claim that legalized abortion somehow prevents women from carrying a pregnancy to term if they'd like. (I'm serious. Scroll down and read from where Still Hurting jumps in.)