I have not observed what you describe. But what I can tell about crypto topics (not only on HN) is that a quality of discussion use to be low while the amount of such discussion is very high. That remains me one of the most famous mathematical meme about Fermat's Great Theorem. There were a lot of people with no math education who use to desire to prove the theorem. And there are too much of people who use to tell something about crypto while have no ability to tell anything wise. What about throwaway accounts, I am sure this is not a problem at all. Just set your "showdead" option for yes and you will see how much of job is doing here invisibly.