The debate on whether Die Hard is a Christmas movie is irrelevant.

Die Hards subtext is much deeper.

John McClain represents the working class American, notice in the movie that John only trust working class people, the cop, the driver, the security guard who he banters with.

Hans is the complete opposite of McClain in that he represents Greed on a massive scale.

Holly, Johns wife represents America torn between two world ideas and pulled by the allure of greed.

the watch becomes "americas bribe"

it becomes symbolic that letting go if the watch finishes Gruber.

Outside of the Nakatomi Plaza sits the symbolic government in the form of police and FBI, they operqte by the book and Hans knows every move they make. it shows how government is powerless to stop this.

notice the similarities between Ellis and Hans, they look the same. Ellis thinks he speaks Hans language.

As far as Christmas, it's used as a tool to illustrate the point. use a massive consumer holiday to explore greed.