Bonhoeffer went against the churches of his day because the Jesus of the bible wasn't being followed. Today it's the "warrior" Jesus that's being touted, one who never existed. When politics and power take over any Christian entity, it always led to disaster.
Even when the U.S. introduced the concept of seperation of church and state, it was for the explicit purpose of promoting religion. The U.S. founders axiomatically assumed religion was necessary for morality and self-governance and believed that a free market of religions (as opposed to state religion) would lead to increased religiosity [0]. And, interestingly, it seems they were right as the countries with state churches have all seen massive religious decline while the U.S. is one of the most religious countries in the world (especially when you filter out the elite class, who as secular as Europeans).
The danger is that politicians co-opt religious institutions to help legitimize their regime and bolster support. Marsh's biography of Bonhoffer describes exactly this process.
[0] George Washington's Final Address: https://www.presidency.ucsb.edu/documents/farewell-address "Of all the dispositions and habits which lead to political prosperity, religion and morality are indispensable supports. . . Let it simply be asked, Where is the security for property, for reputation, for life, if the sense of religious obligation desert the oaths which are the instruments of investigation in courts of justice? And let us with caution indulge the supposition that morality can be maintained without religion. Whatever may be conceded to the influence of refined education on minds of peculiar structure, reason and experience both forbid us to expect that national morality can prevail in exclusion of religious principle."
https://www.metafilter.com/80588/Jesus-who#2514085
The story of the temptations of Christ is a familiar one. After forty days and nights of fasting, the devil came to Jesus with three temptations. The first was to turn stones into bread, the second, to throw himself off the peak of the temple and have the angels catch him, the third, to have all the kingdoms of the world. We could summarize these as temptations be comfortable, to be impressive, and to be powerful. I am inclined to believe that those are also the three most common temptations of the church. Until recent years, the American church was offered each of those and gladly accepted them. Christianity was the default religion for the world’s greatest superpower—a position that should have made us tremble with concern that we were in danger of sliding off the path of self-denial that leads to the cross—but it seemed to occur to very few people that having such a position could be spiritually problematic. We built impressive structures, including dining facilities, recreation and entertainment centers. We turned praise and worship into a profit and star-making industry, and we gladly took our place in the halls of power. It seems that Satan offered us the same things he offered Christ, but we responded “Yes! Yes! Yes!” I doubt that the contemporary trends that are stripping away the power and prestige of the church are the work of the evil one—more likely it is the work of the Holy One, who is leading us step by step back to the paths of righteousness.
When Christianity was being introduced to Scandinavia where in from, the church sold Jesus as a warrior God similar to Thor. Jesus remained that way until the late Middle Ages, which is where the first accounts of the self-sacrifice begin to enter our history.
Religion isn’t static, it reflects its followers and the society it exists in. Those three parts of the bible I mentioned earlier are a good example. If you look them up in various bible versions you’ll find very different ways to word them. In some they are extremely “warrior” like, in others the word “sword” is not even mentioned.
In scandinavia you mean? Even still I find that surprising. Gregory of Nyssa, Basil of Caesarea, and John Chrysostom for example wrote on this subject in the fourth century and were all incredibly well known among early christians and through the middle ages.
Some very early detractors of christianity latched onto the weakness and submissiveness of Jesus as being incompatible with their contemporary ideal of manly virtue. Influential early christians like the ones I mentioned accepted that assessment and used it to form the theological foundations of self-sacrifice that have always been present in christianity.
Certainly the warrior-figure conception has always been there as well, it has never been purely one or the other. And it's definitely true that that element has had more emphasis in certain times and places. But, not knowing anything about them, I find it very unlikely that scandinavian christians would have been ignorant of this entire, extremely significant, branch of christian thought.