There are different accounts of the conquest of Mexico. First, look at how the Spanish tell it:
[After telling the Cholulans that they should abandon their Idols, end human sacrifice, and stop practicing sodomy, all of which offended Christians, Cortés asked them through Doña Marina]: To what purpose had they quite recently prepared many long and strong poles with collars and cords and placed them in a house near to the Great Temple? Why for the last three days had they been building barricades and digging holes in the streets and fortifying rooftops? Why had they removed their children and wives and property from the city? [He told them that] Their ill will, however, had been plainly shown, and they had not been able to hide their treason, they had not even given us food to eat, and as a mockery had brought us firewood and water, and said that there was no corn. Cortés added that he knew there were many companies of warriors cached in ravines near by the city to carry out their treacherous plans, thinking that we will take that road to Mexico [Tenochtitlan] and hoping that with the help of those with us to trap us, this night even, to execute their treacherous plans. So in return for our having come as brothers to tell them what Our Lord God and the King have ordained, they wished to kill us and eat our flesh, and had already prepared the pots with salt and peppers and tomatoes. If this were what they wanted, it would have been better for them to make war on us in the open field like good and valiant warriors, as did their neighbors the Tlaxcalans.
Cortés then told them he was certain all had been planned in the city and that they had even promised their Idol, the patron of warfare, that twenty of us should be sacrificed before it, that three nights ago they had sacrificed seven Indians to obtain victory, which was promised them; but as [the Idol] was both evil and false, it neither had, nor would have power against us, and all these evil and traitorous designs which they had planned and put into effect were about to recoil on themselves. That was the speech that Doña Marina translated for them.
The priests, Caciques, and captains understood it perfectly, said it was true but that they were not to blame for it, for they were following the orders transmitted by the ambassadors of their master, Moctezuma.
Then Cortés cried out, "Royal laws command that treason cannot remain unpunished; for your crime, you must die!" Saying this, he ordered a musket to be fired (which was the arranged signal) and a blow was given to them which they will remember forever, for we killed many of them and burned others alive, so that they gained nothing from the promises of their false Idols.
Now, an account by native Mexicans (although subject to Spanish editing):
Here it is told how the Spaniards came to Tlaxcalla, which was [at the time] called Texcallan.
[The first part of this chapter explains how the Spaniards reached Tlaxcala. While there, the Tlaxcalans persuaded the Spaniards to attack the city of Cholula, considered to be a shrine to the idol Quetzalcoaltl. The Tlaxcalans proved to be among the most loyal of the Spanish Indian allies, who were as responsible for the conquest of America as the Spaniards.]
They [the Tlaxcalans] drove them, they proceeded to guide them. They took leave of them after they had them enter their palace. They honored them greatly, they provided them with everything they needed, and attended to them and gave them their daughters.
Then [the Spaniards] asked them: Where is Mexico? How far is it? They [the Tlaxcalans] answered them: "It is not far now." Perhaps in three days you will arrive. It is a very good place. And [the Mexicas] are very valiant, great warriors, conquerors, who go conquering everywhere."
But the Tlaxcalans in past times had been at war with, had risen up with rage and anger against the Cholullans, They [the Tlaxcalans] disliked, hated, detested them; they would have nothing to do with them. So they told [the Spaniards]: "They [the Cholullans] are very evil, and they are our enemy. Those of Cholula are as valiant as the Mexicas. They are friends of the Mexicas."
When the Spaniards heard this, they went to Cholula, taking those of Tlaxcalla and Cempoalla with them dressed for war. When they arrived, they shouted for all noblemen, rulers, captains, chiefs, and also the men of the town to assemble in the courtyard of the gods [probably of the Temple of Quetzacoatl].
When they had all gathered, [the Spaniards and their allies] blocked the entrances, all of the places where one could enter. In the first moment, people were murdered and beaten. Nothing like this was in the minds of the Cholulans. Without swords or shields they met the Spaniards. Without warning, they were treacherously and deceitfully slain. They were ambushed because the Tlaxcalans persuaded [the Spaniards] to do it.
Was it about religion?
Also, don't forget, the Spaniards introduced a pandemic in Mexico which was, effectively, a biological weapon.
I doubt seriously anyone can stand on a soapbox and crow about religious superiority very long before being confronted by one's own prejudice and ignorance. That goes for all of us.
