Personally, I find the things distasteful, but I know from conversations with a couple of members who run such sites that they don't like it much, either.
They are torn by conflict. They have a regular income from their sites. While they personally dislike the content, they have put time and effort in and they are getting a return. If they give up on that market, someone else will step in and take that income, and they will be faced with having to learn another market from scratch.
I wouldn't like that side of the business to fall into the hands of the unscrupulous, I would rather see these transactions operated within a responsible framework, and Acorn is, informally, part of that.
And even though I know that Jesus is my saviour, I don't see what being a christian has to do with it - there's plenty of bonking in the bible.