Point of no return
The 2nd Hussite revolution in Moravia was infinitely better organized than the first one. Once the leaders had agreed on their programme and dealt with the “mounted patrols”, they started to build a common army to defend the revolution. Due to the horrors of the months of mercenary plundering, hiring foreign mercenaries was out of question; thus the rebels had no choice but to build an army of their own. The core of this new army was based on veteran royal army officers, Hussite zemans  and experienced rebel soldiers from the Slovak lands. With funds provided by Moravian towns, they established military training camps where peasant and townsmen volunteers could be forged into soldiers.
Hussite rebels siege a Catholic-held castle
It turned out that their zeal and determination constituted an immense advantage over the mercenary soldiers and conscripted peasants serving in the Catholic noblemen’s armies. One by one, Catholic forts, castles and strongholds were falling to Hussite rebel forces. Captured mercenaries were usually executed without mercy, but the Hussites showed mercy to peasant conscripts, many of whom then joined the rebellion. Catholic nobles who surrendered and converted to Hussite faith were spared as well and could even retain most of their property. The more stubborn one, however, were subjected to public trials, which ended mostly with them being stripped of their possessions and expelled from Hussite-controlled territory. The nobles who were found guilty of aiding the mercenary bands and refused to repent were publicly executed. Though executing nobles was shocking to most of contemporary Europeans, the Hussites believed in Hus’s teachings about righteous aristocracy and thus in their eyes, a noble who committed crimes against the people he swore to protect lost the right to be treated differently then any other commoner. Another prime target for the rebels was Catholic monasteries, churches and Church-owned property, which was expropriated and divided between towns and Hussite aristocracy.
To Ladislav I, the whole affair felt like déja vu; for the second time in his reign he faced a Hussite rebellion in Moravia. This time, however, the situation was much worse than before. The irony was almost overwhelming when he realized, that the army he created to be fanatically loyal was now useless, because he couldn’t count on the willingness of his Hussite soldiers to fight their brothers in faith. After he acquainted himself with the situation, he knew that he wouldn’t be able to walk the middle line and defuse the crisis by making some minor concessions. The rebellion wasn’t directed against him and his rule; the rebels wanted to get rid of Catholic oppression and have their faith recognized as dominant in Moravia. Unfortunately, granting them that would surely enrage the Pope, who was opposed to a mere tolerance of the “heretics and apostates” in his realm. Openly recognizing Hussite faith as being equal to Catholic would alienate most of Europe. On the other hand, if the king tried to suppress the rebels by force, he would risk a general uprising against himself that could set the whole country into turmoil. So the choice he had to make was: did he rather want to risk the wrath of the Papacy, or his own throne?
There was one more thing that influenced the king’s decision, which is often being omitted. When the second revolution began, Ladislav was 41 years old. Though from today’s perspective he was just a middle-aged men with decades of life before him, in the 15th century this meant he was getting old. Most rulers in that time tried to reconcile with God as the day of their death approached, and Ladislav was not exception. He had long believed that the teachings of Hus held some merit and the older he got the more disgusted was he with the state of the Catholic Church. One day he realized that in his mind, he became a Hussite and that there was no way back. Of course he couldn’t admit it in public, so he pretended to be a good Catholic king despite all the disagreements between him and the Pope that appeared over the decades. But now, he felt, the God had given him the last chance to follow the righteous path and end the hypocrisy which had become a part of his life.
Therefore in April 1452, he summoned the Estates of the Realm to Prague to discuss the response to the Moravian rebellion. Representatives of the Moravian Hussites were also invited, which caused many controversies. In a speech he delivered to a silent crowd, he explained that under the circumstances, it was no longer possible for him to conceal his true beliefs. Instead of expected denunciation of the rebels, the king declared himself a Hussite, which was too much for the Catholics to take; they started shouting and booing in an attempt to stop the king from continuing. But Ladislav was resolute. He raised his voice and announced that he had come to an agreement with the Hussites which he presented to the Estates in the form of “Four Articles” and called a vote on whether or not should they become the basic law in the kingdom.
The Holy Sacrament is to be given freely in both kinds to all Christians in Bohemia, and to those elsewhere who adhere to the true faith.
All mortal sins shall be punished and extirpated by those whose office it is so to do. 
The word of God is to be freely and truthfully preached by the priests of the Lord, and by worthy deacons.
The priests in the time of the law of grace shall claim no ownership of worldly possessions.
At this point, the Catholics began leaving the hall in protest to this outrage, but the king called the vote anyway and the Articles (later called Compacta of Prague) were passed. Then he proposed a reform of the Hussite movement into a national Church led by an elected archbishop, and again the proposal was passed. Right after that, Jan Rokycana , a respected Hussite theologian, was elected as the first archbishop to lead the reformed Hussite Church. The king promised to tolerate the Catholic Church in Bohemia to the same extent the Hussites were tolerated before, but declared that the Hussite religion, his religion, would henceforth be the official religion in Bohemia.
Two weeks later, the Pope excommunicated Ladislav I from the Holy Catholic Church and called upon all true Catholic rulers to use their power to restore the true faith in the Bohemian lands. It was clear than there was no turning back now.
Doesn't matter anymore...
 Zemans were lesser nobles in Bohemia and some other countries in Central Europe.
 This was aimed mostly against the Catholic nobles who were abusing their authority and generally to fight corruption all over Bohemia.
 Or John of Rokycany, if you prefer. Historically, he led the Hussite “church” (they were not separated from the Catholic Church in OTL) after the Four Articles of Prague were adopted.