This angle applies to the DAY AFTER two major events -- Christmas Day and the Super Bowl.
Players either go home or do get togethers with family/freinds. Drinking is common. Teams are out of synch in the next game immediately after the break. The result is usually a poor shooting night by both teams and sluggish performance.
Of course, I am exagerrating a bit here -- after all, these are pro athletes. But the angle does appear to have some merit based on the numbers over the years.
BTW, Thanksgiving has not proven to be an influential holiday. I suspect it is still early in the season and players and teams are motivated to get back and play the games. By late December and late January -- however, fatigue starts to become a factor. Combined with a few off days, some partying, and drinking, that hurts the numbers (offenses).
The best holiday DAY AFTER angle is the Super Bowl. Every athlete watches this game. The game also runs late at night (especially on the East Coast). And, the players often party and drink together. It's not a family holiday, which means there's greater chance for distractions. If they play a game THE NEXT DAY, expect the scoring to decline.
I'll try to dig up the numbers if I can locate them.
Nolan Dalla