As one of the ‘seasoned posters’ on that thread, I really find this unhelpful. If I in any way contributed to the thread being deleted I would like to know how, so that I could decide whether I can try not to do whatever it was again or post on other boards where freedom of expression is interpreted in line with my own interpretation.
I went to have a bath, then watched some of the Winnie Mandela film on tv, and when I got back the thread had gone. I don’t know, therefore, what was posted in my absence, or how long it lasted after I left, which means that if the deletion was meant as a rebuke, I honestly don’t know whether it was aimed at me or not.
As far as diversion goes, for what it’s worth, IMO it is fine if it is just ‘thread drift’, which happens naturally. As has been said, people can bring it back on topic easily enough if they want to, but sometimes threads just run their course. Where I find it annoying though, is when posters deliberately sidetrack in order to avoid replying to questions, or to divert attention from the fact that they are losing the argument, perhaps because they are unable to answer the thing they have been asked.
As I said on another thread, and has been said on this one, deletion of a whole thread just causes ill-feeling, both amongst posters, as it is easy to assume that someone has asked for it to be deleted if they think (wrongly) that they are being victimised, and between posters and moderators, as sudden deletion is disrespectful to people who have taken time to post thoughtful replies on both sides of the argument. Delete individual posts, or PM a poster who is seen to be going too far, but deleting a whole thread is heavy handed and (IMO) unnecessary on a board for adults.