I don’t see you’re points. Why would organically kept animals suffer more from from parasites? The problems with parasites often emerge in overcrowded stables and less in spacious environments (also organic).Yes, DE is a waste of money. It doesn't control lice or parasites, and it's bad for chickens to breathe the dust.
Since raising chickens, I have changed my mind about the merits of going completely organic. Organic "remedies" like diatomaceous earth or fragrant herbs are at best ineffective half-measures. I still feed myself and my birds organic grain and produce, but if my birds (or I!) have trouble with fleas, lice, mites, or other parasites, I use modern medicine to cure them (or myself!)
I no longer buy organic meat in the grocery store, either. I used to insist that all my meat be raised completely organically, but I now believe that it's cruel to raise animals or birds to suffer with parasites or other ailments that can quickly be addressed with permethrin, ivermectin, or amprolium.
After all, I wouldn't let myself, my family, or my pets suffer when an effective remedy is available -- why should I require that my birds or my meat suffer?
Nope, no more organic meat for me. "Grass fed", "hormone free", "cage free", and "free range", YES; but "organic"? NO.
Where I live we have to deal a lot with red bird mite. And DE is even used by the factory farmers because the red mite has become resistent for the permethrin and most other mite killers are forbidden for the food industry bc they don’t break down easily and they are poisonous for the humans who eat the eggs and meat too.
Yes, I do use DE. Once to eliminate a light bird mite infestation. And after that to prevent them for coming back into the coop. I use it as a paint (mix DE with a little water) , a few spoons in their favourite dust bath area, under the bedding in the nest boxes. I also use a little tobacco and lavender in the nest boxes. I have sand on the bottom of the coop.
I never had problems with other parasites.
Giving you’re flock lots of space, healthy feed and a natural environment is also a way to prevent trouble with parasites and illnesses. Less stres and no GMO feed -> less health issues. So far (7 years) I didn’t use medicines or poisons and I prefer to keep it that way. For that reason I don’t buy chicks or chickens but buy fertilised eggs and raise my own chicks too.