Anyone who has been politically active is well aware of the anger exhibited by those on the left. You can't even put a bumper sticker on your car or a sign in your yard without fear that some lefty will vandalize your property and they seem to get a pass. Michelle Malkin has put together a list of some of the left's more outrageous behavior. It is important to inform yourself so that you can pass the knowledge on, however because her post does deal with the left there is a lot of crude and vulgar behaviors on display.
There is a video on her post called "Obama Supporter Gets Violent". You will see the police stand by and do nothing on the first incident, while and Obama supporter becomes completely unhinged. If you have been politically involved you probably have seen and experienced some of this already, however a lot of people have not and don't follow politics. Which Party is the violent extremists? It is the left.