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.
The solution has been mentioned in the threads you linked, and I haven't seen any argument against it - let users share their experiences and/or question job postings in the replies. Heck, the author responded to my comment and had mine not been detached, people could have read the exchange and come to their own conclusions. You're simply protecting the companies with this type of one sided moderation. The way to combat fraud isn't to prevent people from speaking out against it.
If you aren't capable of telling what postings are real/not real (and fair enough, it's a hard problem) what makes you think you can do the same for the replies?
I'm sure I'm not alone in feeling like it's very one sided, and in the current market which heavily favours hirers over seekers it's just another thing going against the seekers. Who often have real concrete stressors like the threat of homelessness.
Either that or remove the rules that by your own words are unenforceable, so people aren't mislead into thinking this board is more curated than, say, indeed or LinkedIn.