Bohemian Rhapsody was played in live aid 1985, I think he wanted to play this because it's a good song, I don't think there were any other reasons for playing this song, maybe to hype up the crowd. I think it's very possible for a musician to start a big concert like Live Aid.
Kanye West has been able to support BLM and I feel like it's actually made an impact on some peoples life, a lot of people follow rappers ideals like a moth following a light.