" who claims to be a Christian" no more then you or I "claim" to be a Christian. We know about him but how many know you other there here? What about all those that "claim" to be Christian yet watch TV/Movies and then read all those books written/directed
It's not really non-Christian authorship that makes a product objectively immoral, though. I loathe anything with puppets, like
Sesame Street; but I'd be hard-pressed to say that watching
Sesame Street is immoral. I think it's definitely immoral to force children to watch it... but that's another matter. OP is talking about products and services that are objectively immoral- specifically condemned in the scriptures: Murder, Sexual immorality, Idolatry, theft, deception, etc.
The OP's question is really about the seller. The buyer is accountable to God;
for sure- but the seller is
more accountable. The buyer stumbles; but the seller casts the stumbling block- and casting the stumbling block gets you in a lot of trouble. I tested this once, because I was a real idiot- it turns out the bible is correct. Even Johnathan Davis knows this, in his song to Brian Welch-
You write it, so you'd best believe it.
You sold it now your soul perceives it.
If a product or service is ultimately for sin; then I don't know how we can justify selling it- we're servants of sin if we sell sin! and we can't have two masters.
With respect to Brian Welch
specifically , KoRn specializes in selling temporary catharsis for rage and despair... but
Brian has the CURE for rage and despair. If you have the cure for a disease, but you are selling the drug that treats
the symptom of that disease.... because it is more profitable... if that's what's going on, then I might have a problem with that.