Since it is being brought up, I have been following Boteach's articles about this, and semantics aside, he only has seemed to present six "arguments".
1. Book censure is anti-intellectual, close-minded, contempt for scholarship, and against the spirit of Judaism.
If this doesn't make this “scholar” an ignoramus, I don’t know what does. I would expect a “scholar” to know about “Ben Sirah” and other “Seforim Chitzonim” prohibited by Chazal. This venue is not the place for detailed discussion about this, but for a detailed summary about this can be found in Encyclopedia Talmudis – “Chochmos Chitzonios”.
2. Boteach attacks Rabbi Schochet for referring to him as J, and not as J****, and inconsistency about the issue.
Again ignorance. The GR”A (Y”D 147:3) writes regarding the prohibition of pronouncing the names of other “gods” (the loose translation is mine): “There is no prohibition other than with a name given as a divine name, but it is permitted to pronounce the name of a person given a common name even after he is subsequently deified … and in many instances in the Talmud, the name of that man and his apostles are mentioned”.
Those words speak volumes: It is permitted to pronounce the name of that man. The intention is pretty clear, if you don’t need to say the name, it is inappropriate for us to do so.
3. His Jerusalem Post editorial cites a whole shopping list of hateful comments from bloggers as proof that the ultra-orthodox are radicalizing and becoming more close-minded.
Is this guy for real… judging a culture by blog comments? I wonder what he thinks of the DDF community?
4. Some of his opinions accord with that of the Yavetz.
… and contrary to the opinions of every single other Rishon and Achron! The Yavetz also had other ultra-controversial stances, and his opinions on these matters are rejected by his contemporaries and successors.
5. His book will earn us more Christian friends.
Where I come from, they say not to discuss certain things at the dinner table, one of them being religion. There is a reason for that. And I don't think anyone appreciates an outsider (i.e. a member of another religion,) claiming to have the "real inside story" of that religion.
6. His book will help combat missionaries.
The missionaries must be laughing. They prey on ignorant people, and tell them "you can still be Jewish - just believe in J, and that will make you even more Jewish". Now, they can add, "Look, even an 'orthodox rabbi' says so!" And since missionaries are masters of distortion, the details of what Boteach said will not matter, they will (quite easily) twist his words to get their distorted message through to their target audience.
In conclusion:
I just checked out the bookcover on Amazaon, and in this case, I think that you can judge the book by its cover. Above the title, Kosher J, it states that Boteach is also the author of Kosher S**. Pure sensationalist.
I might just add that even in his Yeshivah days, it was an “open secret” that Boteach kept a New Testament under his bed. Its his “Girsa DYankusa”.