[quote=@FacePunch]
<Snipped quote by The Kid Lantern>

Thanksgiving is a celebration of a successful harvest. It has nothing to do with the genocide of the Native Americans. It's purpose is similar to the Harvest Festival in the UK.

If you want an international holiday celebrating wholesale slaughter, you could argue Armistice Day fits that description. Although I personally think of it more as a celebration of the end of the Great War, and not the Great War itself.
[/quote]

This.  In early America, there use to be multiple "Thanksgivings" for, as FacePunch said, good harvests or thanks for something.  In fact, Thanksgiving was more popular than Christmas for a long time (the Puritans believe that it was a Pagan festival).