All of what you mention may be true, but it is also a convenient 'catchall' for screwing with people. The Trooper isn't exempt from a one finger salute.
How is society served by issuing a ticket? How is it safer?
This cop would be better off patrolling for real criminals instead of trolling for finger flippers. But I guess that ticketing finger flippers and court appearances is a hell of a way to earn a living and not have to bother with real and potentially dangerous criminals.
Anarchy is minimized.