It's the 1792 "Betsy Ross" flag

They like it because of its symbolic connection to the revolutionary war because they consider themselves brave revolutionaries fighting against oppression.

In reality, of course, they're chickenshit fascists marching FOR fascist oppression and regression to a more primitive and unequal society.

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

White Nationalists have big hardons for big sexy Vikings and their imagery