Perhaps it's best not to speak on behalf of the rest of the world. I fully support the officer. I think I understand what was going on. What the video did not show was the officer advising the young woman that he was giving her a lawful command, not a suggestion. By not obeying the command to get up and walk with him to the office, she was violating the law and was under arrest. He then asked he to stand and place her hands either behind her back or on the wall, so he could check her for weapons before he handcuffed her. She refused to comply. At that point, he used as much force as was needed to affect the arrest.
Yes, he was larger than her and stronger than her. Part of his job is not to get injured while making an arrest. If you are gentle with someone, they can rake their fingernails across your face, kick you in the groin, bite you.
What this school needs is a class to teach students to respect the law enforcement officers they will cross paths with in life, not challenge them and make them use force. I have a friend who was driving drunk when a police officer tried to pull him over. He didn't understand the law and kept driving into a residential area near his families home. He purposely pulled into a private driveway, thinking the police could no longer follow him. He followed that stupid move with another. He tossed his car keys out his window, thinking that somehow might save him. Nope. He was arrested for drunk driving. At least he didn't refuse to take the breath test. That results in a separate charge. By having a drivers license, you are agreeing to take a breath test if asked to do so by law enforcement.
I think the school should make an example of the young student and expel her. Let her family find a new school to take her in. She appears to be on a fast track to a career in the fast food industry.