I understand your frustration, completely!
Up until recently, we had two Mastiffs - a brindle male (who passed away from osteosarcoma in April) and an apricot female (who we still have). Of the two, people seemed to always be more intimidated by our male, including our vet. He was a total mush; he never met a stranger and didn't have a fierce bone in his body. Even when he was suffering from a painful tumor and the effects of cancer, he was pure love. Our female, on the other hand, is very wary of strangers and has been known to growl and snap at strangers that approach her too quickly or in what she perceives to be a threatening manner.
But I don't know how many times our vet requested to muzzle our boy during visits, especially visits that required a more invasive or stressful procedure (Which, I understand - most dogs tend to react to pain defensively. But Knox was a gem and never so much as raised a lip. Ever.). Every time she asked for one, I would reassure her that he didn't need a muzzle, but she insisted. It's interesting to me that she has never once requested that my female be muzzled, even though she's growled at her on several different occasions and I've told her many times that Roux doesn't tolerate being handled by strangers very well and is a bite risk.
