Murder Inc didn't shoot them. Supreme Team did. And they weren't rappers, they were a drug gang.
Also the guy who killed John Lennon said he did so because Lennon was a hypocrite, which is true, and can be derived from the fact that he lived his life in the complete opposite manner of the messages he presented in his music. Whether the guy was mentally ill or not, you can't rule out that his music was a factor.