> why do we not see it very commonly or with such variability across countries?
If you don't see it, it is because you have closed your eyes. It is across countries and reported in main stream media all the time. Rap music is a core part of ongoing gang conflicts in many countries, apart from the general violence and sexual crime it inspires and glorifies.
> How can we say the problem is the music rather than other things going on in those people’s lives which are more unique to their experience than a musical genre?
Then how can we say that the problem is anything that somebody has posted on social media or broadcasted? If I make rap music about dealing drugs and killing people and I also deal drugs and kill people, and many of my listeners deal drugs and kill people. What is the difference if I make a social media post about killing people and then me and my audience kill people? The difference is that one behaviour is celebrated - and romanticized extensively by certain types of persons who feel no empathy at all for the victims.
I never said that rap music is the only thing causing people to commit crime.