I always find that view, in itself, also a curious phenomenon seeing as our tradition comes from the Church of England, which is patronized by the state. Even that ECUSA
Thanksgiving in its true meaning is a fine American tradition. Unfortunately, it has become more synonymous with gluttony than with being thankful. I physically cringe when I hear someone refer to the holiday as "Turkey Day." I find that disrespectful of the meaning of the spirit of the day, and downright demeaning of the turkey. I mean, if I was a turkey about to be slaughtered, I would hope I would be sacrificed as a Thanksgiving offering and not as an offering to gluttony.
I suppose that is one of the reasons the church keeps it as a Mass option with its own prescribed lectionary readings and all. Being Thankful is certainly what the Mass is all about, as it is described in various places in the BCP Cranmerian language as a "sacrifice of praise and thanksgiving."
But what does it mean to be thankful. Do most Americans even really understand the concept anymore?