American Thanksgiving celebrates the joining of cultures between the pilgrims that landed at Plymouth Rock and the local natives because they wouldn't've survived the winter without the natives. The events you're describing (Columbus's raiding) was almost 200 years prior. I'm sure you could find a connection between the two, but without Columbus I think it's likely Europe would've begun to colonize North America sometime in that 200 year span.
Different holidays, dude.
Not that you can't grouse about the mass slaughter of indigenous people regardless.
As for the original topic: I have no idea if I'll even have the day off work. If I do, I'll be at my in-laws', where dinner is large and very festive. Last year I missed a proper dinner because I had a fussy overstimulated baby on my boob, trying to unwind her.