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?

If you set up what is clearly a perfect marketplace for drugs, and you know it's going to fill up with drug dealers, and it does fill up with drug dealers, and there's one goofball that decided to sell a hamburger.... you're not an innocent guy who is running a hamburger marketplace.

It’s not not the same thing either.

The purpose of eBay isn’t to facilitate illicit transactions, doing so is abusing the platform.

SR was very much for illicit transactions.