I think that is a general 'rule' for most breeders as well, not just Bengals, again, it is the one bad apple, a breeder giving papers before neutering, either through inexperience of not caring enough. I do think that if ALL registered breeder rehomed pet kittens already neutered then it is a big step in the right direction. I am not saying that breeders are the root of all evil, what I am saying is that if those engaging in breeding animals for love rather than profit took the lead many will follow. Having said that there is always someone out for a bargain, be it a cheap kitten to begin with, or recouping the cost of a valuable animal.
I am sure that the vast majority of people who use forums to gain advice and knowledge about their chosen breed and in fact their chosen animal ( I have experienced it with rabbits too), will follow advice from breeders, rescues and their peers and neuter their animals. I do think many people are influenced by those around them.
In my experience (of a whole two cats and an afternoon in a rabbit rescue) it is those who do not have the support of forums like this (and the bengal one), who encourage the use of vets, neutering, and proper care, who neglect their obligations and responsibilities to those in their care.
Evie and Ava could have had relief months ago, if their previous owner had de-flead, unfortunately Ava must have been tormented by them for months, as much of the fur on her back end has been chewed away in an endeavour to get some relief from the fleas.