It's simply not Christianity
As I watch what is going on in our culture, I am convinced more than ever that the church needs to do a better job of talking about the death of Jesus and its meaning.
Sadly, what we hear too often about the death of Jesus is that he died to save us from our sins. I would point out that this is an after-the-fact conclusion. As the church tried to figure out why such a good man was killed it looked to its Jewish scriptures and discovered there some help in explaining the unexplainable. His death was not senseless. The historical reason Jesus died was that he was a threat to the power structure--the religious and political power structure. He was a victim of their authoritarianism. So when modern Christians see the Jesus story as a means to promote the powers-that-be, they are missing the significance of our fundamental story. When Christianity becomes a means for power and its promotion, when it sides with the powerful at the expense of the powerless, it is denying what happened to our hero. Sadly, though, many in our era use the Jesus story to defend and promote power and power mongering. Flag-waving Christian nationalism is simply one example of that. And as such, it simply isn't Christian.