Rap early on wasn't gangster in nature. It was more in the 90s that the whole "gangsta rap" thing caught on. The style of rap itself isn't necessarily bad. While it's not really to my taste most of the time, there were some early rap songs that were more innocent in nature.
It went bad much more recently than a genre like country music which for a very long time has had a consistent theme of promoting alcoholism. When I'm in stores where country music is playing on the intercom (which I also am not particularly fond of) just about every song is about drinking beer, being at a bar, or taking shots of whiskey. Many of them are also about irresponsible sexual behavior such as picking up a woman at a bar and having sex with her without dating or getting married. Not that there's anything wrong with a beer or liquor now and then, but for just about every song to be about that is very unhealthy. There was a black guy once at my job who made the comment that country music is often just as dirty as rap music, it's just that they phrase it in a different way. Instead of the hos, it's country queens, and instead of the gin and juice it's beer and whiskey. Both genres also frequently mention weed.
The really frustrating thing is that then after all that degeneracy the same singer will sing some kind of Christian-themed song as if all the bar fights, alcoholism, fornicating, etc. were Christian values.
Basically any kind of popular musical genre is going to be degenerate most of the time because the world itself is degenerate and people are overall very sinful in nature.
As Muman pointed out the song in this thread seems to follow a reggae sound. This is also troublesome, especially when you look into the origins of that form of music. However people in the target audience for the video will probably relate better to that than if he were to use a more Jewish form of music.
Generally I think people should mostly embrace things from their own culture. For example I don't think it's very good if some white person makes an entire career out of rapping, etc. when they could be involved in something more native to their own cultural background. However sometimes it's ok to use different styles of music to achieve a goal.
I think this song was very well done and pointed out a lot of bad things. I wish he would have mentioned more of the horrible things that have gone on in the USA from the government to the people, like the whole MKULTRA thing, but he did bring awareness to a lot of world wide human rights abuses so that in itself is a good thing.