NYC is very safe for an American city, but London is not particularly unsafe for a UK one; its violent crime rate is about average for England as a whole.
You are right. Should not have relied on the most likely LLM-generated description attached to the data. I trusted it because I already had the wrong impression that it was less safe, but that was just because the raw number of crimes is high because it is very populated.
As a general rule of thumb, probably never trust anything an LLM says; they're bad at things.
(I'm particularly unsurprised that they'd get confused about _London_, because, well, what is a London anyway? https://en.wikipedia.org/wiki/Greater_London . Even _human_ writers sometimes get confused about stats for London.)