There is no such thing as counter advertising in the US. No line has been crossed. If Mr. Shamm's book is crap than it's crap, and we have the RIGHT to say so. Not only that, but we can even advise people to boycott products for any reason we want to (unfair labor practices, unethical behavior, heck we can even say the author is evil and wants to promote human genetic mutations if we wish) The closest crime to counter advertising is Slander or Libel, but that involves lying about a product, and I don't think that anyone has lied.