So would you all be happy for your child to be man-handled out of a room if the teacher thought it necessary, in whatever way the teacher thought best?
Yes absolutely. And once I'd got hold of my child, they'd get another pasting for making such a situation in the first place and not doing as the teacher told initially.
I think we need to make a huge distinction here. Just because they can...doesn't mean they will. It's like the police can use reasonable force. It doesn't mean they will automatically taser a guy for driving 33mph in a 30mph zone.
It's about giving teachers the support IF they feel they need to do something. For too long teachers have felt powerless. I note some teachers think they don't need the powers. Great...perfect....don't use them. But they are there for the times you need to without having to worry about the repercussions on your job, getting sued and reams of paperwork.