Comment by dang
How do you propose that we enforce it, even if we had the resources to do so? We can't tell which job ads are real and which ones aren't, just as we can't tell which posters in "Who Wants to Be Hired" are real and which one's aren't. There's a lot of fraud and heartache on both sides of this transaction right now. Sorting wheat from chaff is an unsolved problem. To work on that, we'd have to become specialists in it, which is not going to happen.
If you want, you could take a look at some of my past explanations about this as well - they're listed in this thread: https://news.ycombinator.com/item?id=45094610. If you do that, and still have a question that isn't answered there, I'd be happy to take a crack at it.