Being forced to sit is physical but hardly violence.

If you've been in a position of authority with kids somewhat recently, you know that the old "because I say so" just plain doesn't work anymore. If a kid starts playing Roblox videos on his phone during class I don't see the harm in yanking it out of their hands or forcing them to another room. What solution would you take that doesn't involve any physical contact at all?

Striking kids is a different thing entirely.