The fact that you simplified this case is troubling too. They were not marching peacefully expressing their first amendment rights. They were blocking traffic. Impeding the free movement of hundreds of people.
Every one of these people should be personally sued for damages. I was blocked by these idiots coming home from Boston once. I missed my plane and had to spend $200 to reschedule my flight. So I had to spend overnight in an expensive airport hotel because I had already turned in my rental car.
The next flight was full because of all the other people who missed it. And so I missed a whole day of work the next day. Also a $50 charge for missing a schedule dental appointment without 24 hours notice.
The total cost was about $1,500 bucks.
I don’t have any problem with arresting her for blocking a road. Throw the book at her. That was not what the video showed.