I think TFA does not make this very clear, but it really depends on what "tourist site" is. In the past nobody went to London to take a picture of a phone boot

I think TFA does not make this very clear, but it really depends on what "tourist site" is. In the past nobody went to London to take a picture of a phone booth, but you did take a picture of a phone booth anyway. You'd go to the Horse Guards spot to take a picture, not to enjoy the horses. In this sense, regular people do visit a spot just to take a picture, and have always done that.