School is a waste of time anyways. Why not get vacation for something that already wastes your time? Once December ends and Winter Break is over the amount of schoolwork that you do gets bumped up from about 5% per month to 20-30% per month. This begs the question, why are students forced to stay in school for months when half of the months they're there they do 5% of schoolwork per month?
I do agree that it does waste educational time, but the kids do need a break to explore other aspects of life. They could spend the time exploring hobbies or even visiting a historical site. Or they could spend their 3 months in front of the television like everyone else.