I don't know if he is dirty or not but I don't know why everyone assumes because he is a vet, he is dirty.
Anyone close to the industry knows how it goes, at an average farm: vet recommends X course of treatment; owners/trainers don't want to wait, don't want to spend the $$, so they go for plan B, which is usually the cheaper route unless the horse is "worth it."
The most successful trainers (I'm talking top level) have astronomical vet bills, don't kid yourself. Imagine having that kind of knowledge available every day. I would LOVE to have a competent vet train my horses.