Lets get real here. Both sides have nutjobs in their base, but its quite obvious that the Republicans right now have a significantly larger number of nutjobs in their base then the Democrats have in their base.
Being you are up there in NYC, I don't think you really have an accurate picture of how extreme many in the Republican base have become. Those New York Republicans, they are anomalies. They are not representative of typical Republican activists in the south and parts of the midwest. The birthers, the deathers, the fundimentalists, that's your party's base right now. So yeah, you can find plenty of examples of extremists in the Democratic base, the types that called Bush a war criminal and protest WTO meetings and the like, but it's not a majority of the Democratic base like the nutjobs are not a majority of the Republican base.
To get an accurate picture of what they base of the Republican Party looks like you need to get out of NYC and go to an Assemblies of God revival down in Tennessee or Arkansas. Talk to those people for a little while about current events. Get to know them, that is the party base. So don't get mad when someone points out the nutjobs in the party, its not like they put them there.