Exhibit A: The Internet.
This is something I tend to see around practically any language learning methodology - a very vocal minority will undoubtedly step in and question the credibility of the teacher, debunk the teacher's methods as ineffective and claim their own as superior. Personally, I welcome some degree of debate on all of the above; I feel as though these are important things to take into consideration during the long path toward fluency. There comes a point, however, when a debate such as this surpasses the boundaries of ad nauseum and dares venture into the point of no return - the realm of sheer pointlessness, where the original points which really mattered - quite simply, getting one's L2 from point A to point B - are long forgotten in favor of endless bickering (on both sides).
I've done my fair share of criticism on figures such as Khatzumoto and Heisig, myself, but at least I recognize the merit and wisdom of what they teach, and the importance of trying new things, experimenting, and maintaining a fresh level of diversity while keeping things both efficient and fun. This doesn't mean that I disrespect either of them, of course - quite the contrary. To put it another way, I also voice political dissidence frequently with the way my country's government handles foreign affairs and economic matters (among many other things), but I still love my nation.
I believe it's important to consider that, as knowledgeable as people such as Khatzumoto, James Heisig, Steve Krashen, Steve Kaufmann, Alexander Arguelles and Stu Jay Raj are (to name but a few), none of them can ever be considered the prime authority on language learning - their experiences are unique to themselves, after all. There are so many factors that come into play, such as one's own native language, previous languages studied (if any) and environment that going entirely by another person's directions, opinions or guidelines is almost certainly a recipe for failure in all but the most astute and dedicated learners. Using their successes as a basis, I've been able to find a comfortable balance between everything I've learned from them while still adapting a system that is unique to my own needs as an individual language learner who aspires high fluency in Japanese, and eventually Mandarin.
In the world of language learning, there is no right nor wrong way to do things. There is no central doctrine, there are no rules which state you must do this, or mustn't do that. Whether you drill sentences with an SRS every single day or not, whether you spend four or more years learning a language in academia or not, whether you do nothing but watch television and read comics or not... Everything you do is simply a means to an end - becoming fluent.