There are (sadly) thousands of such stories, YouTube videos, etc. about photographers getting assaulted and intimidated when legally taking photos in certain areas. This is basically the same thing at an even more technological level.
My speculation on this: A lot of people in security have such boring jobs that even if they don't feel intimidated by photographers, they relish a chance to play big, get a buzz out of the day, and look like they're "doing their job."
My speculation on this: A lot of people in security have such boring jobs that even if they don't feel intimidated by photographers, they relish a chance to play big, get a buzz out of the day, and look like they're "doing their job."