Well, I've read most of this thread, and most of the 'antis' seem to boil down to two major arguments.
1. It will 'corrupt' young gamers.
2. It will damage the reputation of the game.
Both are highly flawed.
With regard to the first, we have to bear in mind that there is a real issue of DM responsibility. The DM has a responsibility to only introduce the BoEF if he feels it appropriate, and if the players are mature enough to deal with the BoEF in an adult fashion. A high school DM who introduces it to a group of 14-year-olds is clearly acting in an irresponsible manner. Aha, though- what about irresponsible DMs? Personally, I don't think that this makes a huge difference. Irresponsible DMs can introduce pornography, the GUCK (though I'm not sure how this compares with the BoEF) or any other material already. If a DM is irresponsible, he is irresponsible regardless of the BoEF; if he is responsible (as I hope most are) then he will only introduce it if appropriate.
As for tarnishing the reputation of the game, this is somewhat self-indulgent. Dividing the general population into the hardcore antis (a la Jack Chick), gamers and the rest, it's clear to see it has little impact on any group. The hardcore antis are largely out-of-touch (Chick's website does not feature the Book of Vile Darkness, for example) with even the new material that they could bash gaming with. In any case, they will be against gaming whatever it does. These people are frequently against Harry Potter and Pokemon : they just seem determined to attack gaming and fantasy irrespective of what it does. The BoEF will not alter these attacks, even if they do get wind of it. As for gamers, I think that by and large it will not deter them. Like the BoVD, most retailers will tend to keep it until wraps, and probably sealed. If the gamers want it, they will buy it. If not, they won't. I can't see anyone really quitting DnD because of the BoEF, especially as it isn't core rules. An erotic fantasy section in the DMG might deter some, but a separate optional supplement will make no difference. As for the population at large, we flatter ourselves that we are even on their radar. I've never seen a major national daily or weekly than even mentioned Dungeons & Dragons (except for a film review of the awful movie), let alone an obscure non-core supplement. People are largely uninterested in the intricacies of the gaming world. Some may have vague notions of the standard stereotypes of long beards, slightly unwashed adolescents and such like, but they will neither know nor care about the details. After all, the much-vaunted moral outcry against the BoVD never materialised, and that was actually published by WotC themselves.
Really, I can't see what all the fuss is about. There was hysteria about the BoVD, there is hysteria about the BoEF. In the former case, there was no moral backlash, no public outcry, no mass boycotts. I fail to see any of these materialising as a result of the latter.