Final answer:
The claim that no Spaniard ever spoke against the exploitation of natives is false. Bartholomew de las Casas is a prominent example of a Spaniard who became an advocate for native rights and fair treatment.
Step-by-step explanation:
The statement that "Not a single Spaniard ever voiced over their exploitation and oppression of native peoples" is false. There were several Spaniards who were concerned about the mistreatment of native peoples during the colonial period.
One notable figure is Bartholomew de las Casas, who was initially an adventurer benefiting from the encomienda system but later became a vocal advocate for the rights and fair treatment of indigenous populations. This is exemplified by his efforts, which contributed to the issuance of the New Laws of the Indies for the Good Treatment and Preservation of the Indians in 1542, aimed at improving the conditions for the natives.