Certainly. One of the most known figures against many colonization practices was Bartolome de las Casas. You can read about him here. The Catholic church gets a lot of crap nowadays for destroying indigenous cultures with overbearing and violent Christianity. While this is based in fact, it's still an exaggeration that ignores how Domincans and others were the primary advocates for the humanity of the Americans. Figures like de las Casas considered the locals as other humans who needed to be brought into the church (more so than the Jews and Muslims, who were kicked out of Spain in 1492 and were held under suspicion even if converted).