You wouldn't go to a knitting forum and pay to advertise your erectile dysfunction pills, not unless you wanted to waste your money and time. Shilling shitcoins among maxis is equally nonproductive. It's true there should be some way of suppressing these kinds of posts, but the same applies to any other sub-teen spammer wanting to harass or post porn.

The fact that porn isn't spread far and wide on SN is a testament to the effectiveness of requiring payment to post.