I'm no expert on the law, but I don't think it is unlawful to restrict access to filming as long as the person can reasonably film. She was right up in there which is too close. Officers usually setup a perimeter around their business for crowd control so they don't get jumped by a group of people. The kid had already stepped in, the woman was really close and shouting, the dog got riled up, and some other woman was being held back. Crowd control is needed for the safety of everyone involved.
Call me a dreamer, but I'd like to live in a society where police officers can enforce reasonable laws safely. I realize there are going to SHTF scenarios where that goes out the window a bit, but that doesn't describe this case.