I make and sell soap. The soap contains an ingredient that anyone can use to make bombs. Some people buy my soap only for that purpose. I know because they literally tell me how they use my soap. I can remove that ingredient but I would loose a lot of sales.
The police finds my soap in the lab of someone who blew up a building. Some people died. Was it my fault, knowing how it was being used? Did I do anything illegal? Unethical? Immoral?
Having done some internet things (email stuff) that have been abused by others I always felt obligated to make the abuse as hard as possible once I found out about it.
I am not sure about the legal standpoint, but from a moral one I would have felt bad running the business knowing it's regularly abused to harm others and I am not doing anything against it.
> I can remove that ingredient but I would loose a lot of sales.
Or: I can remove that ingredient but it goes against my principle of not accepting constraints.
> Some people died. Was it my fault, knowing how it was being used? Did I do anything illegal? Unethical? Immoral?
Interesting thought experiment, but no, I don't think it's llegal/unethical/immoral to sell that soap. But in practice this sort of business will change their formula to avoid bad press and regulation.