The longer video on the BBC news website shows you exactly how the security there did handle it. Surprisingly they weren't grabbing people by the neck but instead escorting them out by walking alongside them and guiding them onward by steering their elbows once in a while.
This is indeed how all security is headed. Get more security around the people to reduce the need for restraint and simply give them no other way to go but to move with security out of the building. Which is exactly what you see in the longer video.
No pushing, shoving or neck control. Just a simple line of protestors being swept along relatively calmly by a lot of security.
I don't disagree with you but it requires numbers ..... a single security person would have had to use exactly the same methods to control her until numbers overwhelmed her.