Interesting topic. Keeping away from Nairn and the original thrust of her allegations, I'm appalled at the apparent ease that so many seem to find in referring to themselves as 'expert ' in whatever and then proceeding to fleece the gullible.
I've had a staff member ( with her own horses ) frank her stupidity by spending thousands with unqualified and barely competent practitioners getting a young horse broken in, having riding lessons, etc, etc, with predictable results.
With a bit of advice and common sense the 'unbroken' horse came to hand quickly and kindly, her riding also improved from abysmal to fair on a tractable horse, even to the point where she managed to ride slow trackwork for a local trainer.
The point being that these unqualified practitioners are able to make money with considerable risk inherent for many who get sucked in.