The mere fact of my taking pictures in public does not make me a special representative of the photographer class so that my every act speaks for "photographers" and may enhance or taint the perception of photographers in the world.
Sites such as these (of which there are many)http://www.peopleofwalmart.com/http://youarenotaphotographer.com/
may be funny the first time you look through them, but if you think about the subjects as real people with lives, friends, etc, it becomes clear that we all open ourselves up to humiliation if we happen to pick our noses or pull on our shorts absentmindedly, or even dress badly one day.
So yes, actually: whether it's fair or not, everyone with a camera in public is a representative of "photographers."
I see many people wearing crosses as religious symbol -- am I to judge a whole religion by what one of them does?
It's an "in-group" vs. "out-group" thing: my
beliefs should never be impugned based on a few bad apples, but yours
? Well, it's just proof of what we should expect from your kind!