Bands of a variety of genres like: Heavy Metal, Hard Rock, Alternative Metal, Thrash Metal, Industrial Metal, Metalcore, Hardcore(Punk), Deathcore, Nu Metal, Death Metal, Post-Hardcore, Gothic Metal, and Black Metal.
I always thought the technical term for it was white metal. And yes there are Christian metal bands but it really depends on the specific group. Some are Christians playing metal, some are bands playing Christian metal. Same with black metal, some play for satan and some just play because they can. It all depends!!!
Christian metal is not a genre, because it is not a separate style of metal. Christian metal means that the bands play metal music and use Christian lyrical themes, however the music itself can be either heavy metal, thrash metal, death metal etc.. (all kinds of metal). So to me Christian metal is an ideology and not a genre because the music is the same as every other kind of metal, but the lyrics are just different. In my opinion band members have nothing to do with that, because there might be a metal band with all members being Christian and if they don't write Christian lyrics, they won't even be classified as Christian metal. So, if the band has Christian members it does not mean they play Christian metal.
Yes, Christian metal is a very specific genre because there are people who like metal who would not want not to listen to lyrics that may be offensive. You may not be able to find a Christian Metal section in a store specifically, but it is a specific genre. Like Christian rap, or Christian folk...and yes, those exist as well.
Christian metal is a genre. It can be played by anyone but I suppose non-Christians would not normally be interested in playing Christian music so I guess it would normally be played by Christian bands.