It's transferred anger and fear. Christians sense the growth of secularism, the increasing numbers of openly stated non religious people, the indifference towards religions of Millennials, and this scares them. So they invent imagined wars against their silly festivals and the rest of their Bronze Age beliefs, both to rally their followers and to have an 'enemy' that is 'persecuting' them.
It's obvious and pathetic really. What they are having a war against is change and social evolution, and no one wins that war.