As for Paul Ryan, well, I honestly couldn't tell you the political affiliation of most of the musicians I like. Odds are I strongly disagree with some of them on any number of issues. I don't think that's odd.
I would say that for most musicians this is true, however Rage Against the Machine is known as much for being very vocal about politics as they are for their music. And the majority of their songs are pretty in your face, so even if you don't follow what the band gets up to, if you even half pay attention to the lyrics you'd realize they hate everything rightwinger stand for.
Sample Lyrics:
Killing in the Name Of: Chorus is literally a repetition of "Some of those that work forces, are the same that burn crosses." (Calling out racist cops before it was cool.)
Bulls on Parade:
Weapons not food, not homes, not shoes
Not need, just feed the war cannibal animal
I walk tha corner to tha rubble that used to be a library
Line up to tha mind cemetary now
What we don't know keeps tha contracts alive an movin'
They don't gotta burn tha books they just remove 'em
While arms warehouses fill as quick as tha cells
Rally round tha family, pockets full of shells
Sleep Now in the Fire:
The lie is my expense
The scope with my desire
The party blessed me with its future
And i protect it with fire
I am the nina, the pinta, the santa maria
The noose and the rapist, the fields overseer
The agents of orange
The priests of hiroshima
The cost of my desire
Sleep now in the fire
In short, Paul Ryan is an idiot.