I saw your initial question as well, and I’ve been trying to find a coherent way to write about it, so I apologize that it took so long to get back to this. Unfortunately the answer is sort of like that “well yes, but actually no” pirate meme, haha.

There were actually lots of different perspectives and interpretations of the crusades even in the Middle Ages. Not all Latin Catholics were unanimously in favour of crusading, and other types of Christians certainly weren’t, especially when they were targets too! Here is a previous answer I wrote about this: Was there any Christian opposition to any of the Crusades?

Criticism of crusading is also tied up with the very beginning of the Reformation. Luther’s 95 Theses are mostly about indulgences, which were originally granted for participation in crusades, but had since become heavily abused. But Protestants weren’t unanimously against crusading, just like Catholics weren’t always in favour of it. There have been many different trends in the historiography of the crusades since the Reformation, but the most important common thread is that they are almost always reactions to or commentaries on contemporary events. There’s really no such thing as a neutral examination of the crusades! Here are some of the major trends.

The Reformation

An important question during the Middle Ages and Reformation was whether any warfare ever be justified, scripturally or otherwise. Ancient and medieval philosophers had argued that it could be, and philosophers like Augustine of Hippo were often cited in support of crusading. But medieval thinkers disagreed over whether the Pope had the authority (spiritual or secular) to wage such a war.

By the Reformation in the 16th century, the question was not so much whether war could ever be justified - the answer was clearly “yes” - but who or what could justify it. Both Protestants and Catholics (who were also going through their own counter-Reformation) agreed that wars against Turks or other Muslims were justified if they protected Christians in general, or if it was a political war, empire vs. empire. A war couldn't be holy or just, however, if it was waged to enrich only one part of Christendom (the Roman church).

Protestants felt that they represented the true Christian church, but that meant medieval Catholic history was part of their own history, and they had to reckon with that. In fact they often agreed with the goals of crusading even if they disagreed with the implementation. John Foxe, for example, otherwise famous for his history of 16th century English Protestant martyrs, also wrote a “History of the Turks” where he blamed the failure of the crusades on the corruption, impurity and idolatry of the Roman church. But if it was possible to remove corruption from the church, as Protestants believed they were doing, then it might also be possible to reform the concept of crusading too.

All discussion of the crusades during the Reformation occurred in the shadow of the Ottoman Empire, which had conquered Constantinople in 1453 and was still expanding into Europe. The Ottomans conquered Hungary in 1526 and besieged Vienna in 1529. Christians in western Europe felt they were in very real danger of being conquered by the Ottomans. The ideal response would be for Catholics and Protestants to work together to defeat a threat that they all faced.

It didn’t always work out that way in practise. Despite the claims of philosophers and legal theorists that the Pope had no authority to wage a war, there were several “Holy Leagues” led by the Pope against the Ottomans. And of course there was constant warfare between Catholics and Protestants that prevented them from uniting. For some Catholics, there was no difference between Protestants and Muslims - both were a heretical deviation from orthodox Christianity (Islam was often considered to be a heretical form of Christianity).

Medieval crusades had been led against heretics, and some early modern Catholics were happy to fight a new crusade against Protestant heretics. Protestants sometimes also looked back to those medieval heretics as fellow reformers - Albigensians, Waldensians, Hussites, etc., were all part of a continuous protestant tradition. So, both Catholics and Protestants could appreciate the idea of crusading against the Turks, but for some of them, the bigger enemy was each other.

Nationalism and national histories

The first “histories” of the crusades in something resembling a modern history book were written in the 17th century. There is a bit of pro-Catholic/anti-Catholic sentiment in them but the defining feature is really nationalism. By now there was a clearer definition of a “state” and a “nation”, something that didn’t exist in the Middle Ages. Now that French authors, for example, had the concept of a distinct unit called “France”, they anachronistically transplanted that idea back to the Middle Ages and claimed that crusading was a uniquely French concept.

The earliest collection of medieval crusade texts to be printed (using the relatively new printing press) was by Jacques Bongars in 1611. Bongars was French but he was a Huguenot, a Protestant - and yet he called his collection of texts the “Deeds of God by the Franks”. He clearly approved of crusading as a concept, and also associated it with the French nation. From the Catholic side, probably the earliest modern history of the crusades was by Louis Maimbourg, a Jesuit priest. Maimbourg praised the medieval French crusaders and implored the current king, Louis XIV, to live up to the name of his ancestor (the crusader Louis IX) and continue the crusade against the Turks.

But the context is important here too - France had suffered from the Wars of Religion in the 16th century, and the Thirty Years’ War was raging in the neighbouring Holy Roman Empire when Maimbourg was young. Perhaps a crusade could help unite France under one ruler.

Meanwhile in England, 17th-century Protestants were also ambivalent about the crusades - maybe they were the greatest example of medieval superstition and papal abuse, but the idea of crusading was still useful. In the philosopher Francis Bacon’s famous summary:

“the Philosopher’s Stone and an Holy War were but the rendez vous of cracked brains that wore their feather in their head instead of their hat.” (quoted in Tyerman, pg. 56)

Thomas Fuller, the first English historian of the crusades, condemned papal superstition as we might expect from an English Protestant, but also thought there was some good in crusading, and like the French, hoped another could be launched against the Ottomans.