Marines (especially in the infantry) don’t get many chances to get away from their duty station. The mandatory holiday leave block for Christmas is one of those chances, and some Marines will take advantage of it for more than just a return to their Home of Record [where you enlisted from].
I’ve seen leave requests get denied by the chain of command for a variety of reasons. Usually, it’s because the Marine wants to go do something like spend 14 days drinking in Vegas, road-tripping to Tijuana, or flying to another country to marry their catfish. Essentially, anything that your chain of command thinks you probably won’t return from, is going to get denied.
Of course, a real skating champ saves up their leave days so they can take 2 months of Terminal Leave at the end of their enlistment.