Wishbone: I'm assuming this was in response to something said in post #16, #17 or #18 (which are now gone for some reason), rather than a spontaneous necro of a thread from 2015?
Does anyone know why those 3 posts are gone or what they contained?
No idea what the posts said as they're not there to read now. Grargar suggested they were spam, so I wouldn't be replying to spam. Rather, as happens when a thread surfaces to the front of the forum list - I selected it based on the thread title, read the first post and a few after that and replied to it based on that. I did not read the entire thread or even scroll to the bottom to even realize it was a reopened necro post, or I probably wouldn't have bothered replying.
Such is the nature of things when people necro old posts, others aren't always going to read every post in advance or even the last few to determine if it is a new or old thread before replying. That's life. If it's a big problem then people could submit a wishlist entry to GOG that any posts that are beyond N days old get flagged as locked and closed and can not ever have additional comments added. By the very nature of them not being locked it implies that there are legitimate reasons why someone might want to post on them again perhaps, and it can't be both ways. So it is ultimately up to GOG to decide whether posts older than N days are allowed to have further comments or not, and if they do allow it, then there will be people occasionally adding comments to old threads, some of value, some not, some trolls necroing old threads, and some innocent people replying without realizing it is a necro'd thread. It's just a fact of forum life for all of us in the end. Best thing for us to do is to not give it any time, thought or attention and just click close and go to the next thread post of interest.