The tack problem has hit the Tour de France as well. You can read about it on several sites.
Again, I don't condone this behavior, but it is becoming clear that in many countries, including this one, people are getting fed up with cyclists. We already saw it in New York last week. It's tough times in this country, and in others. When people are working 2 and 3 jobs just to pay the bills they don't have the patience or time to sit behind some douche bag driving 30 or 40 MPH under the speed limit.
Let me say again, don't stoop to their level. Use your politicians and local governments to get these people off the roads, do it the right way.