So don't you think the BNP is racist?
can't speak for NS but I imagine he does. But I think you are misunderstanding what NS is getting at here.
As far as I can see it is the issue of the intention of the bakers at play here - that is did they intend to discriminate against the person or the idea.
Tatchell is arguing that it is the idea they did not like, not the person. I find that distinction a little disingenuous but I am enough of a realist to see that it causes issues that are not easily resolvable.