Is it as simple as stating, "I support metal, not National Socialist Black Metal"

but personally I wouldn't be able to resist poking the retards with a stick.

Like everyone said, review the music just as you would any other. People review Cannibal Corpse because it is good, entertaining music, not because they support rape, gore, etc.

It's a lyrical theme, just like any other. You're reviewing the music, not the ideology.

Completely wrong, that's basically only reviewing half of a finished product. Disregard the ideology if you want, that's your own opinion, but there is nothing wrong with others being put off or having their opinion affected by one. I think people who say stuff like this don't really understand a lot of things. For one - that people make music because they feel strongly about something. Sometimes they just feel strongly about making cool music, or supporting their scene, but other times it's more serious, and we can't just ignore that all the time.

If music inspired by passionate hatred for black people was musically excellent according to your tastes, but the source of inspiration was strongly opposed to your ideologies, it still shouldn't matter. The music is excellent regardless of how misguided the musicians are and what kind of nefarious beliefs they hold. If these beliefs somehow influenced an album's musical aspects, and yet the music was in concordance with your tastes, it shouldn't matter. Only the musical output is important, not the motives and sources of inspiration. For example, consider some simple musical unit such as a chord progression. There is a certain powerful sounding chord progression that you like quite a bit, and most of your favourite songs use that progression prominently. A NSBM musician felt that the same progression portrayed the strenght of his hatred for non-whites, and consciously decided to use this progression in his racialistic music. Even if you don't believe any race to be inferior to any other, you still enjoy the same chord progression this NSBM musician found appropriate for his racialistic music. Even thought he had some partially metamusical motivation to use that musical element due to association with some imagery, the musical element remains unchanged - just as none of your favourite songs featuring this same progression are tarnished by the NSBMer's choice, the song he wrote bears no ideological message. This is because music is completely abstract, and the only meaning it has comes from association and context.

If the lyrics are noticeably obnoxious and you feel terrible every time a beautifully sang chorus praises Hitler, or an awesome scream audibly proclaims hatred for jews, they still affect your enjoyment of the album and should therefore be taken into account in the rating.

Film is not quite as abstract a form of art as music. I don't see how the movie above is relevant to this discussion.

Having a wrong message makes music less enjoyable for me when I hear it than it would be if it didn't have such a message. I know this is the case based on the fact that I have heard things that I liked, later found out that they had a message I disagree with, and then found the music wasn't as enjoyable. This is the objectively reality of my experience and if I was reviewing the music in question I'd rate it lower than I would have before this change occurred.

If your experience is similar to mine, you can use a similar logic to make your judgements and scores.