Most political songs belong to more extreme political views, I’d say. Thus they’re divisive and are more prone to angry music styles. Most people seem to prefer music that makes them feel good, so non political songs are more succesful. There are political feel good songs, ‘we are the world’ comes to mind. So I don’t think its a conspiracy of record labels to keep the masses docile. Plus with streaming services the big labels loss influence, but things have not changed much.