Digging up old threads - why is this a "problem"?

Can anyone explain to me what's wrong with having a question about an old thread?

This thread was not active for a while:
http://www.automotiveforums.com/vbulletin/showthread.php?t=102437
... someone happened on it and they had a question.
Why is that grounds for closing the thread?

At what point are threads not allowed to be added too?

*scratches head*

The grounds is uniformity in action from moderators. 6 months is about the norm, but that thread was well over a year old. It was also a question posed to a member who had a total of four posts, that one being his last. The topic would have been better addressed if he had started a new thread, stating "looking for an exhaust like.... *insert link here*"

a PM in explaination has been sent, i guess another part of it was that i was up late and in a bit of a pissy/asleep mood :)

damn that was a nice looking mr2 though...

well I'm new to this site and what if I find that one paticular thread is helpful and would like to keep it going and find there to be more questions within some of others answers

if you have a specific question, you will probably find out more by starting a new thread, and citing the other thread(s) in your questions... or perhaps just taking what you learn from one and asking for clarification on the issue.