They are not racist
they are nationalist. There is a very important distinction there.
A person cannot control their race, but to a degree they can control which nation they are loyal to.
Nation and race are not one in the same thing. It is made more complicated because of family, but for those who are not racist they could get sperm from a bank of random sperm, and all mothers could be surrogate.
So you end up in a nation at birth, without mother or father, that state controls your life up to say the age of 4, at which point you choose the nation you want to belong to, and off you go there.
They are many races in different national parties around the globe, and to be honest most political parties claim nationalism. I don't why, it is like claiming you are for the people who vote you in.
The BNP is more central than the US democrats, we only have a few extreme parties, that is Labour and the monster raving looney party, for the main. The BNP is mainly about community, and heritage of the culture, they are probably pro keep the castles, pro keep the beer, pro keep the imperial weights and measures, and not for Europe.
Racism at any level is wrong, but if nationalism be wrong, I don't want to pay tax, and I declare independence immediately.