I do believe it is not moderators activity, it could be Bot behavior.
I would no longer post in this forum, if I believed that my posts are deleted without being reviewed by a human and they are all deleted by a bot.
Moderators cannot monitor my activities for 24H/7 days to find me online and delete old posts within an hour or half hour after posting a new discussion.
You are right. Moderatos don't waste their time on monitoring your activity.
Moderators review your posts if they are reported. It's not that they are always looking at your post history to check if you have made a new post.