Lainey was there as a protester given that her family is of mixed blood, she has plenty of muggleborns in her family tree. She feels like not giving basic medical care to non Purebloods is just outrageous and she will not just stand by and let the Foundation do what they are doing.
She was very vocal with her large sign she had held up and the fact that she made sure she made herself heard by shouting and chanting along with the crowd. Lainey didn't really care if she was going to get reprimanded for this at work, she felt it was her duty as a citizen to be there.