Here's my take on it.
Typically... any of us who really get our dogs out in public, in classes, in trials, on the street... are very aware of peoples perception of our dogs.
This is even more evident when you have a dog that is not readily identifiable to 'joe public' as a bull breed. You would not believe the different breeds people think Luke is, boxer, swissie, border collie mix, etc., even "dog people". Now I generally find that people who meet him unknowingly, and really like him, are much more receptive when I tell them what he is. Although he is a registered amstaf I DO refer to him as a pitbull to help open peoples mind, and prefer to skip the pitbull/amstaf debate, to the public.
When I am around the same crowd with Vega who is much more typical looking, there is a big difference in peoples perception and reaction. She is seldom approached by people who aren't already familiar and comfortable with the breed.
Because of this... it is my experience, that responsible, aware, bully owners make it a point to have their dogs better behaved and better trained than the average dog, just to be given a fair shake.
I also generally find that pet owners who love their pitties, but don't have as much control over them, don't get their dogs out as much because they realise the perception, and they keep them at home.
I also find the idiots (for the most part) who abuse, neglect, and take pride in an uncontrolled or aggressive dog tend to keep them around the neighborhoods and atmosphere that accepts or supports that behavior.
Its our job to educate them all.
You cant say they DONT bite. They do.
You have to educate from all angles. Showing them with babies and bunnies isn't enough. Sometimes showing people what they fear the most... and showing them absolute control and temperament, CAN make a difference to some people (as Chris has done), that all of the foo-foo stuff in the world wont convince.
I have seen police dogs who don't have nearly the control of some sport dogs... but those dogs often are going to your children's schools. They might not be doing protection demos, but people assume they are trustworthy and under control. Parents seldom complain.
I don't think people whose dogs aren't HIGHLY reliable, have no business doing demos for anyone. But showing control where people don't believe dogs can be under such control, can help.
Especially when you want to educate people to understand a dogs body language and intent... nothing is as good as examples. The best seminars on body language and understanding dogs I have seen have included demo dogs (rescue dogs mostly) that exhibit different types of aggression (which could be "safely" triggered for example). No videos, pictures, or illustrations can demonstrate these things effectively.
That seminar was by Lillie Goodrich and I have yet to go to a BETTER seminar on canine communication, and body language.
I don't think protection sports should be done irresponsibly or taken lightly. I don't think it should be done in a public event that is not attended by people who are there for their education. Some people who aren't ready for it, are probably not going to see the image you are trying to present. But people who are willing to be educated, whether they ever plan on training protection or not, HAVE increased their knowledge and understanding of it. From Chris. On this forum. In a positive way.
Also understand, protection work should not be assumed to be because of ego. Speaking for MYSELF. I did a limited amount of bitework years ago. It was not for protection. It was not for ego. Very few people even knew (not the best way to stroke your ego). I did it to educate myself in as many aspects of how dogs work, as possible. Its my responsibility as a dog trainer, and people trainer, and learning as much as I can about instinct and behavior, is my passion (not just a hobby). And even tho I had a very well trained/bred GSD at the time, I did it with my most stable dog. Willie. Protection training didn't make him aggressive or unpredictable. It did not change peoples perception who knew him. If they liked/trusted him it didnt matter... if they didn't like him, they didn't know about it, but it wouldn't matter.
I didn't buy a BC to learn herding (and my dogs didn't learn to chase livestock), or a bloodhound to learn tracking (and searching blood trails for wounded deer, didn't make them bloodthirsty or deer chasers). I did it with my bullies. Because they are the dogs I love... because they liked it... and because I could.
I do understand all of your positions and opinions on this topic. Just trying to put a few more considerations out there... from my perspective.
"Pedigree indicates what the animal should be;
Conformation indicates what the animal appears to be;
But, Performance indicates what the animal actually is."
- author unknown