I dont' have time to read every post, but:
Here is my two cents:
Sometimes I watch a TBN station called JCTV. They show music video's of Christian rock bands.
I remember seeing Christian hard metal guitarist who looked just like marilyn manson. Eyes rolled back up in his head so all you could see were the whites of his eyes, and black stuff/make up oozing out underneath his eyes... Honestly... THAT's Christian? In my opinion, no way! It's appearance is of the world- not of Christ.
Metal is NOT Christian, no matter how they may describe themselves.
Your argument can be summed up as, "one metal musician I saw had facepaint and looked 'worldly', therefore he is not a Christian and metal cannot be Christian."
May I ask you a question? How is Christianity defined? Does wearing make-up make one un-Christian? Is a Christian not a Christian anymore if he wears it? How is "looking worldly" defined? Technically, it could mean doing, listening to, watching, or wearing anything that's widely popular in the world. Is a Christian not a Christian anymore if s/he plays football, listens to death metal, goes to see a popular movie, or wears what's currently in style?
You can't point to one person and say that he's not a Christian because he does X, Y, or Z. That doesn't work unless something he believes actually goes against the definition of Christian--because Christianity is a belief system.
Say, if a person were to say "I'm a Christian, but I don't believe in god" or that he believed in several gods, or that he believed in god but not Jesus, then we can conclude that he is in fact NOT a Christian because being a Christian necessitates a monotheistic belief in God and Jesus' existence, sacrifice, and resurrection.
"Who art thou that judgest another man's servant? to his own master he standeth or falleth. Yea, he shall be holden up: for God is able to make him stand."~Romans 14:4 KJV
My intended point with the verse I shared (above), is that it's not up to us to judge our brothers and sisters in Christ based on things that are not clearly defined in the Bible. And certainly not assume them to be non-Christians.
Is the Bible against black facepaint? Some might say yes and quote Scriptures to support this. But when you come down to it, unless it's clearly stated, it's debatable.
Which, I don't care for facepaint myself. I think it looks ugly.
And hey, some Christian artists, of all genres, may be doing their thing entirely for the wrong reasons. I think God can use them anyway, just because He's God and can do as He pleases. Personally, Christian music does a lot to encourage me, including hard rock and metal. If I'm questioning whether I should listen to it or not, I look at the message coming from the lyrics and go from there.
Anyways, not trying to bombard you or anything and sorry if I'm bugging you. God bless.