The salute
There is actually an interesting history. It started as Roman salute, US adopted in 1892, called it Bellamy salute, as an official part of "Pledge of Allegiance".
https://en.wikipedia.org/wiki/Roman_salute#19th%E2%80%9320th_centuries_United_States
And US changed it in 1942 I think because it looked too similar to the Italian and Nazi salute, which has been called the fascist salute at the time, and US declared war on Germany and Italy in 1941.
Though fascism was not a negative term at the time, merely a different idea, it became negative after the war.