There was a thread "Could a black hole be a result of matter/antimatter polarity reversal?" in the relativity forum earlier today which appeared to be an innocently over-enthusiastic question, partly based on a very speculative article at physorg.com. I replied a few times for example to explain that the mainstream view is that "anti-matter" is not the same as "negative mass" and that black holes don't go anywhere. However, the thread seems to have completely vanished. A similar situation happened a couple of days ago when I tried to reply to another similarly confused thread (about the Cavendish experiment), although in that case the evidence was admittedly mounting that the original poster was probably not open to scientific discussion. In the past, such threads would typically incur a warning about speculation or non-mainstream ideas and would be locked if necessary. In the last case I hadn't yet seen any evidence of anything other than jumping to false conclusions based on a over-speculative article. When I've spent time and effort trying to help someone with a complicated question, I'm not happy to find that my efforts have been just deleted without trace. Is it really necessary to do this rather than just adding a reason and locking it?