Choral Public Domain Library

I am trying to collect songs that chronicle various peoples struggles for spiritual, economic and political freedom.

Any suggestions?

A modern grand master who still writes and sings such songs is David Rovics. On davidrovics.com you can find texts and recordings of many of his songs in the section "songbook".

If you are interested in historic songs, try to locate the special archives in your country and make dates for visits. In Germany, e.g., there is the "Volksliederarchiv" or special collections at the "Akademie der Künste" (e.g. songs from concentration camps or workers' songs).

Some pieces to throw into the mix in case any fit what you're looking for:

Years ago I heard the New York Choral Society sing Paul Alan Levi's Dayenu, A Passover Oratorio, which covers both the Exodus from Egypt and an escape from a concentration camp during the Holocaust. There was one particular movement that was so haunting and affected me greatly; I don't remember which movement, but I think it had aleatoric spoken parts.

Horizons by Peter Louis van Dijk, SATTBB
A moving lament for the San bush-men, commissioned by The King’s Singers from the Dutch/South African composer Peter Louis van Dijk.
https://www.kingssingers.com/products/horizons/
https://www.youtube.com/watch?v=A8bLCikf7vc

Melissa Dunphy's "What do you think I fought for at Omaha Beach?" is excellent and moving. It's taken from testimony before the Maine Senate in support of marriage equality by a soldier who fought at Omaha Beach:
https://www.youtube.com/watch?v=Z60BgGsbCs0

Also, the repertoire of https://www.lapenachorus.org/ includes some great songs:
https://www.lapenachorus.org/music/index.php

For example, I like El Aparecido, by Victor Jara, which appears 42 minutes into this video:
https://vimeo.com/192212433