Would you help a stranger?

Just watched a program called 'would you help a stranger' on BBC 2. Really took a tole on me, the way certain people react to being attack. i can't judge as i was not there but i cannot relate to how people can stand back and watch someone completely innocent get beaten.
One statement on the site "Two years ago, Mark Reid – aged 25 at the time – had just parted ways with two friends after an evening together. His friends went to wait for a bus on London's Tottenham Court Road, when they were cornered and attacked by two men. Reid ran back, and told the men to leave them alone. "One of them grabbed me by the neck and the other punched me," he says. "I punched the guy holding me by the neck, and when he fell to the ground, we started walking away." But the incident was far from over. "One of the men ran towards me carrying a roadside bin over his head. There were lots of people around – over 50 – who saw him throw the bin at me," Reid says. "As I dodged it, I tripped over myself. He jumped on top of me, pinned my shoulders against the ground and sunk his teeth into my lip." Reid begged him to stop, but the man bit further, taking 3cm – including the muscles of the corner of his mouth – out of his face. "I heard screams from people who were watching but no one came to help. He spat the lip out next to me, and ran off, his face covered in my blood." Over the coming months Reid underwent five operations of reconstructive surgery, yet despite the trauma, he is sanguine about the reaction of the witnesses. "My attacker was screaming, wildly aggressive – it's understandable that a stranger wouldn't intervene."
how could over 50 people not intervene, even with a phone call or a witness statement if not psychically. I will never understand it. One Girl on the program got her face kicked and jumped on in a fully crowded bus, she screamed for help yet no one would stop a unarmed 15 year old girl, beating her or even try to stop the bus. That's sick. What the hell is our world coming to? How no one cares about public security, safety or even justice. Not even a statement.
A recent report found that British people are the least likely of all Europeans to step in if they witness a crime. But would you intervene to assist a stranger in danger? But i guess that is the stereotype of being British, that we don't say anything of what we see or think.
Having a conversation with my mother in general, she spoke of her traveling on the train a couple of weeks ago. A small 13 year old boy in school uniform was being filmed by two boys and getting beaten by another, on a fully seated train. How out of all those people ranged from 13 to 70 years old, men and female; My 62 year old mother was the only one who actually intervene even if she only Shouted at them, it seemed to stop them and the cruelty that was all so humiliating and public for the young boy.
Makes me disgusted more than angry how dare they think they have that right, it all seems so primal. I think i may take it too personally. If you were getting attacked wouldn't you want help, even for a stranger? If your loved one got attacked in public would you want them to be saved and someone intervene? I would.