Probably has more to do with hip hop since Houston might have had a louder sound. So people probably make the assumption of that.
I’m a city data poster so I knew of the crime rates by simply researching it from there.
All thought
@DalMem mentioned something about black areas specifically. That might be something good to research because I do believe if you took out the white areas in all cities the murder rates would change.
For example I often use to hear San Francisco had some of the worst black hoods but it was hidden by all the white and gay people who call the city home more than black people.