There's a lot to denconstruct here but to break it down it really is many factors leading to a total societal failure. People, parents, technology, culture, laws, education, standards.
In the olden days the possibility that this murderer would walk away without having at least some sort of male onlooker verbally confront him was very low. If there were a group of male friends or someone with a weapon themselves or a gun this animal probably wouldnt leave alive. Now, most men are inexperienced in even the most basic of real fighting or confrontation.
The ease of having a readily available video camera that can transmit the recordings in real time across the internet to millions of other people is also a factor. Everyone wants to be responsible for "the next big thing" in the hopes their video goes viral because a few minutes of fame and the possibility of a paycheck is more important than helping someone else out. Dont get me wrong, the technology have absolutely come in handy but the bad consequences now far outweigh the good. Countless good samaritans and innocent people have been burned for being recorded and identified coming to the aid of others by wicked individuals, juries, judges, law enforcement, and vigilantes. So now they go against their own nature despite what happens because there will always be one jackass pointing a lens. They know the system is rigged against them and its NPCs absolutely will froth at the mouth to make an example of them.
Why bother risking your health, life, family, and finances?