de las casa was actually both. a conquistador-turned-ordered monk.

i think the point is still quite salient though, de las casas was not the first representative of the church in america and many within the church were quite content with what was happening in america--to heathens--as it were. it's quite right to question the moderating influence of the catholic church when it appeared late and in actuality quite feebly (when its representatives were even interested in the new laws)

what is most responsible for spanish colonization not totally exterminating native peoples and ways of life is not de las casas and directives from the metropole, but a heap of credible indigenous power. limitations on colonial excesses was more about preventing uprising than it was humanitarianism, and though the usual historical overview is "spain conquered x, x, x, countries lets move on to the 18th century already" rebellion was constant after the conquests and very often not overcome by spanish military force. accomidation, detente, and autonomy with native groups underwrite the Big Maps of spanish colonies in america.

Then you'd have to compare Catholic clergymen to Protestant clergymen (if possible), and Catholic laymen to Protestant laymen. It doesn't really change anything about the argument.