If you are Polish abroad or of Polish descent, do you celebrate St. Nicholas day?

That's like saying "you're breating oxygen, Polly". Not being fair is what he does.

It is odd that he still carries the citizenship of a country whose culture he thinks so little of....

Judging by many of your psots, I think you may have a touch of Irish chauvinism in you. One can be a patriot and be proud of one's country without overlooking its flaws. Both Poland and the US have many vices and virtues, as Ireland presumably does as well. But the subject was not the entire sweep of perceived pros and cons but Chrsitmas commnercialism. And nowhere on God's good earth is there as much of it as in the good ol' USA!

There is a difference between genuine culture and the artificially manufactured pop culture created in corporate boardrooms and on computer drawing boards for one purpose alone: to fleece the public and rake in maximum profits regardless of the socio-cultural and ethical consequences.

There are two major strains of American culture as exemplified by the neighbourly barn-raising and the snake-oil pedlar.
Building a large barn was beyond the ability of a single farmer but when his neighbours arrived they got the job done in no time. He then also pitched in when someone else was building a barn. That example reflects community spirit, cooperation for the common good and the localness of many American instituions and arrangements which stand in marked contrast to the centralism of many other countries. That is reflected today by i.a. popular votes on school taxes and local ordiannces as well as ommunity carolling in the town square and greeting a new neighbour with home-made cakes and other delicacies.

The other approach is circus mogul JT Barnum's famous saying: "There's a sucker born every minute." That is the America of quack remedies, mega-commercialism, outrageous advertising claims (double your money back if not completely satisfied! -- but try to get it!), cheap and tacky but addictive pop culture and the ongoing commercialisaiton of the individual: "Just reach for your credit card and leave the rest to us!"