I’ve been recently reading into Hernán Cortez and his expedition into Mexico and one thing has struck me is the loyalty of most of his men. How did he not have a mutiny when he gave the order to scuttle his fleet?
How could they be fine with scuttling their only way back home to Spanish territories? Or did he send a few ships back to send word of his location to start a resupply line?
Those men had great bravery to destroy their only way back home and march on into unknown lands.
You have something backwards, Cortez scuttled his ships after a previous mutiny in order to avoid his men running back to Cuba (and giving notice to the governor).
From "Historia de la Conquista de Mexico" written by Fransisco Lopez de Gomara, Cortez's official chronist (this is the guy accused by Bernal del Castilo of aggrandizing Cortez):
XLI. The mutiny that was against Cortez and the punishment. There were many who murmured against the election of Cortez as it excluded that land from Diego de Velazquez whose parts they had as serfs, debtors and some as friends... ... then those same people sought to rebel with a brig killing the shipmaster and leaving for Cuba to give notice to Diego de Velazquez... Cortez then verily raged. He burned many of them; taking their sayings, in which they confessed. As such following the time's due process he condemned those most guilty. He hanged Joan Escudero and Diego Cermeño, pilot. Lashed Gonzalo de Umbria, pilot as well and Alfonso Peñate. With this punisment Cortez made himself be feared for if he was bland he wouldnt have lasted. XLII. Cortez finds the natives across. ... and to ensure that everyone would follow him, even those that didnt want to, he decided to break the ships; difficult thing and of great loss... he then begged the shipmasters to spread the rumor that the ships were rotten and unable to sail... everyone believed them on account of being stranded for 3 months, enough time to believe them.
He also made a point of sending relations (misinformation) back to Spain in the following years in order to secure the proper permits:
... he then took the nao (ship) with presents, letters, and relations... latter sending after it an armed carabel, passing secretly through the island of Cuba, Montejo and Portocarrero, so that Diego Velazquez wouldnt understand their porpouse.
According to Gomara, the reason he was able to make the remaining spaniards follow him was a combination of bullying, threat of torture, looting, military victory and finally the promise of gold once the "gifts" from Moctezuma II arrived (so pretty standard command style for the time), remember most of these people were poor mercenaries, pirates, or just plain poor without any real hope of land or a stable life in Spain, almost all of them were drawn by the promise of looting and obtaining land for themselves in the New World.
He also kind of hid from them the fact that he was a fugitive in Cuba, remember, Cortez was effectively a runaway criminal having come to Mexico without buying the proper rights and having disobeyed Cuba's governor Diego de Velasco's direct orders.