Sometimes thoughts have to be written down for no reason, simply because you will try to remember sometimes later and they are not there anymore...this is about the purpose of black metal as a form of artistic expression:
Provocation has no purpose in black metal. As an artist I write the music firstly for myself and secondly for a random audience which happens (for whatever reasons) to like my output. Supposing that there is absolutely nothing which could possibly shock a black metal audience, no taboo for those people that could be broken, the listeners will not feel any provocation whatsoever. Violence, sex, drugs, politics, religion...as a black metal musician you are simply not able to provoke the people you write the music for. Of course, other people may get upset about what you serve your audience, but then, those people are not your audience anyway and you can't even begin to guess what might be able to irritate them.
Taking all this into account I don't view any black metal as "meant to provoke" by default and therefore "shocking people" can only be an unintentional side effect which the artist is barely aware of. The reason for choosing album and song titles, choosing the right words for lyrics, choosing the images for a CD design and so on are based on how I like them to be and not on what I believe people outside the genre might think of them. Reducing any aspect of music to "The musician simply wanted to provoke with that" is rather offensive to hear. As a musician I do things for a reason that makes sense for me, that fits my overall form of artistic expression and not based on how it could affect people outside the genre. The moment we start directing our music at "other people" - meaning people, who are not our possible audience (as said above, a black metal audience can not be provoked by methods of black metal) - we have completely lost our justification.