None of these parties are as bad as the 'center-right' parties that actually win elections and form governments in Europe/Israel/Australia. They provide a useful 'devil' for the existing political classes of those nations, of course. That's not saying I would ever vote for one of them, but I would be far more worried about the Conservative Party winning another election in the UK than I would the BNP scrounging up enough votes to take one seat.
What if these parties actually had good chances to win? Would you actually prefer them over the mainstream right parties? Sorry if I ask, but I've noticed a recent trend among my fellow forum leftists that worries me a bit.
And what would that trend be, if you don't mind me asking? As for the question, I am not sure I would bother casting a ballot if my choices were between folks who want to rob me blind and folks that want to deport all foreigners.