An anti-racist stance has to be consistent, otherwise it's just... more racism. When I went on Anti-Nazi League marches with my schoolmates, the hope (as I understood it in my hormonally left-wing state) was for a colour-blind world of equal treatment and opportunity. All racial differentiation was bad.

That was before Diversity(TM).

Now, race - which has bizarrely transformed into 'culture' - is something completely sacralised. OK, 'celebrate difference' ... but isn't that just another way of maintaining separateness? If you can celebrate Black, the argument against celebrating White ends up looking pretty weak. Next thing, you have the BNP themselves using diversity as their justification. A page of their site titled "Is The BNP Racist?" has a long list of ethnic interest groups and associations (National Black Police Association, Asians In Media, ... ). Then they blithely say:

In reality, none of these organisations are “racist” — each and every community has the inalienable right to look after its own interests.
This includes the indigenous British folk, and the BNP is proud to be the party which stands up for the rights our [sic] folk and country, in exactly the same way that all of the above organisations stand up for their folk.

Which appears sound for about four seconds, until - duh - you admit that all ethnic associations (including the BNP) precisely are racist, for the very reason stated. What else does "look after its own interests" mean, when "it" is a racial group? That's the definition of racism.