Hip hop music consists of rapping, DJing, dancing too whilst rap music is branch of hip hop music you can say this!
Hope difference between them is clear to you!

How many more must come
(how many more must come)
How many more must go
(how many more must go)
Who were these heroes
(who were these heroes)
We do it here in your name
(we do it here in your name)

I understand this part well and I really like it!
I don't understand everything you wrote!
Thanks for participating