I can understand why Rabbi Lapin is concerned, but the mere existence of those books means nothing. I would guess that, taking all those titles together, their sales are in the low single thousands, and the publishers will lose money on each one, when the returns come in.
How do they make up the losses? Well, it's simple. You see, there's no copyright on one book that's always in demand by those creepy Christianists.
(Also available in the lighter but equally revered Jewish version, approved by rabbis and 100% Gospel-free).
d.o.l.
Criminal Number 18F
I'm sorry, but I don't care how many or how few books these guys are selling. When a group of people start calling for the destruction of the First Amendment and are lionized in the media for it, that's a problem. Let us not forget that the first step in genocide is demonizing the vicytim, and these guys are plugging away at it.