What? He's insulted someone for having differing political views in a democracy. He sounds like a moron and the majority of people I know on every side of the political spectrum would agree.
Oh yeah, I completely agree with you - the first line of my reply was just a cheap joke about how much the LibDems have bent to tory policies since the general election, I certainly wasn't supporting what that campaigner did.
Having said I completely agree with you, I would have no problem insulting a BNP/UKIP supporter, and in some cases people who are right wing but less so (such as being a more-than-average right wing tory supporter), but I wouldn't use a straight-up insult such as "bloody tory supporter", would do my best to insult by making a point on some subject and winning (in my view) the argument.
Actually, to back peddle once more, frankly I'd have no problem just being rude to someone for the fact that they are a BNP supporter.