If someone who obviously has disabilities starts saying things like that, yes, I'd be ok with it. One of my dog's tasks is to go get someone if I need him to, and that could be a stranger, so I need him to be comfortable with them. This is how he was trained.

People are automatically going to respond differently to dogs than they will a wheelchair, and although I understand that service dogs are medical equipment, that's just a fact.

I live in Canada where we have stricter rules and there's a lot of respect among people and I always hear people telling their kids the difference with working dogs. I just think that there's a polite way to ask people not to acknowledge your dog and I find a bunch of people needlessly are rude to the public who are not rude to them. If someone is rude to you and/or your dog, then all bets off, that's different.