Intriguing... the samples I listened to were all instrumental. Are there any songs with lyrics?
Ah, BoF beat me to the jazz angle. I'm listening to Mingus as I read this thread, and there's a lot of uplifting stuff in Jazz ... mostly instrumental, though. (Better Get Hi in your Soul, Wednesday Night Prayer Meeting, Haitian Fight Song...) Although what I'd really recommend in that direction is Charlie Haden's Liberation Music Orchestra. A lot of those jazzified protest songs also exist as somgs, somewhere.
In more pop-like waters, Little Steven's mid-Eighties' stuff is always worth checking out. The Staples Singers' freedom songs (as they called them) are very chant-worthy, Aretha Franklin's
Respect is less of an anthem, but uncontestedly uplifting. Just in general, you'll find a lot of stuff to work with in old Soul records. Late 60s, early 70's.
The Kinks'
Get Up and
Better Things, maybe. Annie Lennox'
Sing may be a little programmatic, but it was written to be exactly that kind of uplifting. And yes, now I'm really just title-checking everything that comes to mind and wasn't written by Bruce Springsteen.