Wrong. Bartolomé de Las Casas latter abjured of every form of slavery and retracted from that statement. Not to mention that he freed every slave that the owned prior to his pro-indian campaign too, in order to back his words with example.
Trans-atantic slave trade, albeit a multi-national global business, it was originally a wholly 101% English creation that you guys controlled for the main part of its existance, and whose blame you latter tried to endorse us. The first "commodity" that Britain fought for trading and introducing in the Spanish-controlled ports was not silver, nor gold nor spices, but slaves. So enough with the ridiculous notion of anglo-saxon moral superiority.
Conquistadores were semi-independent soldiers of fortune that conquered in the name of the Crown, but that is, in name-only. Central authority over their occuppied lands was tenous as fuck, and consequently, that lead to many, many conflicts between the Crown and the Conquistadores and their offspring, which soon became oligarchs.The tragedy of South America was in great part due the fact that these were the same guys (well, their grandsons) that latter independized their countries so they could keep their privileges in place. Natives actually sided with the Spanish Crown fighting agains the independentists, you can guess why.
In addition to that, the Spanish empire's main drive, unfying force and source of balls-to-the-wall intolerance revolved around religion, first and foremost, not race. In just one generation after the conquest, you had Aztecs and Incans occupying higher goverment offices in the Spanish territory, and leading armies in Europe. Noone gave two shits about it because they were Catholics.