In terms of explicitly stating issues, almost every genre of rap counts. Even some bs like Michigan trap can be interpreted as dudes talking about how shitty their lives are because of the social structures they live in.
In the same vain, every time an artist makes something completely new it’s a political statement. For example, right now there’s a lot of trans artists making extremely over the top pop music that would only be possible with modern music making techniques. And although the lyrical quality is often stuff like repeatedly saying “cunt” I can’t help but interpret it as a form of protest.
Because of the internet there isn’t one voice of protest music. Everyone is getting a different feed and exposure to different artists. But so much of it is a form of protest, you just have to look between the lines.
It’s not necessarily a real historical event, but an incredibly important story about liberation of the oppressed that influenced countless real historical movements.
Herodotus’ histories is mostly fictional but you wouldn’t want to forget it. Same with the Iliad/Odyssey, Epic of Gilgamesh, etc