I don't really understand why the O.P. was attacked. His concern was legitimate - It's quite possible those blue-tongues were getting dog food as a staple and it's widely known that cheap dog food isn't a particularly good diet, even for dogs. I can say with confidence that if someone showed images of their monitor being fed dog food on a monitor forum they'd get the verbal/typed equivalent of being tarred and feathered pretty quickly. I also do not subscribe to the 'lizard knows best' line of thought, because all of their instincts have been honed to food available naturally, not to the assortment of artificial diets concocted by humans. They will happily eat the wrong food until they die of obesity, metabolic bone disease or any one of a wide variety of ailments caused by a poor nutritional mix.
There was a classic example of this on this very forum, not so long ago. I spoke to the original owner of this lace monitor and asked him why he fed his monitor chicken breast, rather than a proper diet, and his response was: "but she LOVES it!".
Unfortunately, chicken breast didn't love her - check out the photos:
http://www.aussiepythons.com/forum/general-reptile-discussion-42/lace-monitor-mbd-graphic-169275/