1. There is little point in posting advice for a member who hasn't visited the forum for over 1 year and the thread has been inactive since then.
2. Threads which have been inactive for a year or more frequently contain information which is out-of-date. In one recent example the inactive thread was 7 years old and referring to the Immigration Rules in 2010, which were significantly changed in July 2012.!
3. Moderators simply don't have the time (or the will) to check through these old resurrected threads to check for advice which is no longer relevant.
4. Digging up very old threads clutters the forum with no real purpose if the OP has been absent from the forum for a considerable length of time.
5. I'm guessing that your example of a Moderator asking you not to open a new thread was due to the existing thread on the particular immigration issue still being active. Unless you can post a link, I'm unable to comment further.
As a new member, you may find the guidance in this link helpful, especially point 12:
announcements/read-me-getting-started-t ... 24804.html