It's meant to intimidate. It's like they are "occupying" their own country by raising the colors on their car and driving fast. It's like wearing a Patriots jersey in a Jets bar to watch the game.
If you could dialogue with any of these people, they would have no clue what they even "stand for"
"I love America because of the freedom!"
"Love it or leave it"
But if you ask them what that actually means...how have they exercised freedom in America, what has America afforded them (other than their truck) you'll get no answer