Why Do Americans Celebrate Thanksgiving?

It's probably because Christmas is still illegal over there.

https://en.wikipedia.org/wiki/Mayflower

Although, perhaps, not for the reason you might think.

Seriously. Shouldn't it be Europe celebrating Thanksgiving?

As in;

"#Haw-Haw! The people who'd think of the Taliban as too liberal and decadent are your problem now!"

https://www.timetravel-britain.com/articles/christmas/ban.shtml