Your contempt for men and women who are dealing with aggression and abuse every single day to keep the public safe is despicable. Do you have to do a job where you risk catching Hep C when you try to arrest people who scratch, bite and break skin? No, so maybe you will understand why there is protocol around arrests to protect the officers and public. No one could calm the woman down - she was off her head, abusing ticket inspectors, abusing the police, stopping the bus service - if she'd been a white woman you'd probably think she was drunk or coked out.
Have you tried to restrain and arrest a kicking, screaming woman? They absolutely needed handcuffs because she WASN'T GOING WILLINGLY and getting increasingly violent and abusive. Having multiple officers is a safety measure to protect the officers when someone is as aggressive as this woman was. There are signs in every station in the country that abuse against staff will not be tolerated - what do you think that means?? Do you know how she abused the ticket inspector, what she said or what she threatened, what she threatened the police officers with - you know nothing other than what some bored twat on the streets is saying in a video he took that doesn't show any of her abuse. And the Met are far too decent to release the CCTV footage of her antics on the bus.
She wasted a whole bunch of police resources, delayed the bus service, delayed the passengers because she couldn't be bothered to show her ticket - she's just an arsehole. She doesn't even have an explanation for why she wouldn't. And if you'd been on a bus or train with her trying to get to work and watched her kick off - you would not be anywhere near as sympathetic.