Here's the thing. People come to this forum looking for advice from more experience dog owners, trainers, breeders, etc. They are looking for quality information that will help them raise their dogs.
In this case, the OP was asking why his dog was getting re-infected with fleas, and what to do about it. Instead of addressing the issue, you chose to provide a bunch of misinformation, based on your particular agenda about dietary supplements. When asked to provide some basis for your recommendation, you provided a word wall of non-facts.
You got caught out. Cope.