No - I don't think you can equate a gallery space with the street. This isn't the public domain. In my post I mentioned our city market which wants to know who you are and why you are photographing there. It seemed odd to me at the time, but they are within their rights. My mistake was to think of the place as a public space, which in one sense it is, but not in every sense. When I go through the door of the market building, I am on their property, space for which they have responsibilities, and rights attached to them. One of their stated concerns is that they feel a duty toward their customers - whatever their motivation, some people don't like to be photographed - I don't much like it myself - and the market's main concern is that their customers be happy. Their house, their rules. When I worked in retail, we too would ask someone what they were about if they were photographing in our store.
If I were running a gallery, I would want to let my visitors look at the exhibits without worrying about being watched themselves.
I'm a photographer myself, but I am aware that my photography isn't the only thing that matters in this world.