It may be considered rude, but we live in the United States of America where it is still legal to give hand gestures to people who make us mad.
Carrying a badge doesn't entitle you to abuse your power or force people be nicer to you.
A video was posted on YouTube by user Hillbilly Cop Wednesday with the following description.
"Former Baxter County Arkansas Sheriff Benny Magness cuts off a driver then pulls him over when the driver flips him off. First he says he was speeding, then admits he didn't have a radar detector."
The video depicts an obvious violation of this driver's rights: