The crime rates in other places is irrelevant if the city you've lived in for the last 20 years has become noticeably more dangerous.
This is not "a narrative that keeps being pushed without merit", in fact the people who dismiss such claims are often the ones who live very insulated lives.
Let this be a salutary warning to HN readers that a huge amount of baseless nonsense gets written about crime in London.
Let this be a salutary warning to HN readers that people get needlessly pissy when you question them about the backgrounds of their experiences.