My supporting POV on selfishness motivating human moral values

[Wyrd of Gawd]

I wouldn't all-caps "literally" when the thing you're saying is false.  Thanksgiving is IMPLICITLY CONNECTED to Native American slaughter.  It is "literally" about giving thanks, to the natives and to God, for bounty provided in time of need.

Do you really think that? Do you really think that a celebration in the spirit of appreciating Native Americans was being observed while these same natives were progressively being raped, slaved, and flat out murdered nearly out of existence?

Allow me to enlighten you. After over a hundred years of Thanksgiving celebrations of victories and slaughters of various Indian tribes and villages, George Washington finally suggested that merely one day of Thanksgiving be observed per year in celebration of these "victories". Now, in case there is any doubt about Washington's intentions, observe this piece of his own writing, taken from a letter he wrote to General John Sullivan, which instructs him to attack the people of the Iroguois:

lay waste all the settlements around... that the country may not be merely overrun, but destroyed.... do not listen to any overture of peace before the total ruin of their settlements is effected.

Now, this is the man that suggested the celebration you so fondly think of as "Thanksgiving" be observed once a year, as it now is. 

Does he sound like someone who wished to honor Native Americans?

Good old George was definitely a pure-blooded racist and bigot.  He led the fight against the British so that he could keep his slaves.  And he wanted to kill off the Indians so that slavery could be expanded in their former lands.