Luther’s Lectures on Romans are, on that website, said to be from 1513 to 1516, though most sources say they were written in 1515 and 1516. And it is true, that in these Lectures, we see some of Luther’s flashes of insight on the doctrine of Justification. As Luther’s insights are rooted in St. Paul’s Epistle to the Romans, and these are the seeds which eventually gave way to the Reformation.
But the robust, fully articulate expression of Luther’s theology took time. It didn’t occur over night. This is why he was still dedicating the 95 Theses to the Pope. When Rome took notice, and then responded with harsh condemnations, this took Luther by surprise. He was not trying to offend anyone, he saw himself as simply carrying out his responsibilities as both a pastor and a professor of theology, as a loyal son of the Catholic Church, and obedient subject of the Pope.
There is a narrative that is common to see in Luther a rebel fighting against the Catholic Church–but the historical realities are incredibly more complex and nuanced. Luther did, of course, come to condemn the entire institution of the Papacy as antichrist, and Rome as an enemy of the Gospel–but this is largely what emerged in Luther when the Pope condemned him as a heretic in a papal bull of excommunication, and when he was literally hunted down following the Diet at Worms (which he was able to survive when he was kidnapped by Prince Frederick the Wise, and kept safe where he would be housed and commit himself to a translation of the Bible into German). Luther would leave Frederick’s protection and return to Wittenberg, where he had to confront Andreas Karlstadt who was at one time a close friend and colleague to Luther–but had taken Luther’s name and created a radical re-interpretation of Luther resulting in violence against churches and priests. Karlstadt was a radical and violent revolutionary, and was harshly condemned by Luther, and was driven out of Wittenberg.
So if one wants to talk about a “Protestant” rebellion, we should not be talking about Dr. Luther, but the radicals like Karlstadt, and some of the other radical reformation groups, like the Zwickau Prophets.
Luther took equal, if not harsher, aim at the radicals as he did with Rome. Luther regarded these extremists who subscribed to forms of Enthusiasm as violent and doing the work of the devil.
This is also why, earlier here, I said we should understand that there was no singular “Reformation” in the 16th century. There were several “reformations”. Luther’s reformation had nothing to do with radicals like Karlstadt, the Zwickau Prophets, Thomas Muntzer, etc. Luther, likewise, clashed with Ulrich Zwingli, regarding Zwingli as also radical (for his Memorialism, rather than violent teachings). It would also be wrong to identify Luther’s reform movement with King Henry VIII’s schismatic break with Rome which had nothing to do with Christian doctrine, but with Henry’s desire to divorce his wife.
So there were many “reformations”. The Evangelical Reform movement of Martin Luther and the other Evangelical fathers should be understood on its own historical terms; and while it shares much in common with the reform movement of Calvin, Zwingli, and Knox which has come to be known as the Reform tradition within Protestantism; it is distinct from these as well.
We can, broadly, classify three Reformations.
The Magisterial Reformation (e.g. Luther and Calvin), but we should arguably make a distinction between the Lutheran and Reformed reformations here.
The English Reformation which followed a different path following Henry’s break with Rome.
The Radical Reformation, which was a diverse array of movements which went much farther than the Magisterial Reformers, such as the various Anabaptist groups, Enthusiast groups, and Apocalypstic groups. But also includes explicitly heretical movements like the Socinians and other Anti-Trinitarian movements which arose at this time and which are under the “Radical Reformation” umbrella.
This is also why talking of a singular “Protestantism” is basically impossible.