They don't understand what has happened. See here:
1Co 15:25 For He must reign till He has put all enemies under His feet.
By way of example, during the invasion of Iraq the US Army captured Saddam Hussein's palace. As a kind of "spoil of war", Tommy Frank and several of his generals went into Saddam's palace and sat on his sofa and smoked cigars. They had pictures taken of it. For anyone who doesn't know what happened, they might just as well mistake Tommy Frank for Saddam Hussein. Because no one would sit on Saddam's sofa and smoke cigars except Saddam himself.
Now, walk up to the nest ten people you see and ask them what holiday is celebrated on December 25. They will all say Christmas. That's because no one knows those pagan holidays. The pagan gods have been conquered and no one remembers their names. That is what it looks like when someone puts all enemies under his feet. No one remembers them because their names have been blotted out. But then there are some in more ignorant quarters who scratch around and mistake Tommy Frank for Saddam Hussein.