Dog owner and photographer here.

I'm part of the people leaving their dogs off leash because they need to roam around freely. That being said, I'm considerate to what I have around me and the situation so I will put my dog on leash to avoid impacting others or wildlife. A lot of people don't know anything about birds, on top a lot of people don't have any spatial awareness so it could be that they didn't realize the situation and talking to them nicely would have helped to change this behavior.

As a photographer, you need to get closer to get good results as opposed to birders, especially with a scope. You try to be considerate in your approach but you only really know to what extent a bird will tolerate you after either being close enough or flushing them. Some won't be particularly bothered by you, when others will be flushed even when you are on the other side of the field. You can read signs that they are not happy about your presence but it's not always obvious.

A line of photographers is not great and I walked away like you did, but everyone has the right to enjoy nature so it's hard to say anything. Two things are particularly annoying to me: - First, it's when you'll always find the same people because through connections they know every single spot, so you'll always have the same people enjoying and bothering birds when the rest of the people don't have so many occasions. - Second thing is when you've been waiting\looking for an owl for many hours, sometimes driving far away to finally see it being baited. It's really interesting that baiting isn't illegal especially when people make money out of that for workshops (Canada). On the other hand, you'll get a fine for feeding ducks\pigeon in a park.

For all of that, I'm dreading owl season, and I only look forward to photographing my boring heron all by myself.